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Final Report

The Effectiveness of Providing Labels and other Pre-Purchase Factual

Information in encouraging more Environmentally Sustainable

Product Purchase Decisions: Expert Interviews and a Rapid Evidence

Assessment

Project code: POS013

Research date: May 2018 to January 2019 Date: February 2019

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Document reference: WRAP, 2019, The Effectiveness of Providing Pre-Purchase Factual Information in encouraging

more Environmentally Sustainable Product Purchase Decisions: Expert Interviews and a Rapid Evidence Assessment

Prepared by Dr. Colin Whittle, Fiona Brocklehurst, Catriona McAlister & Prof. Lorraine Whitmarsh

Document reference: [e.g. WRAP, 2006, Report Name (WRAP Project TYR009-19. Report prepared by…..Banbury, WRAP]

Written by: Dr. Colin Whittle, Cardiff University; Fiona Brocklehurst, Ballarat Consulting;

Catriona McAlister, Sea Green Tree; & Prof. Lorraine Whitmarsh, Cardiff University

Quality Control by: Christian Reynolds, WRAP

Front cover photography:

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WRAP - The Effectiveness of Providing Pre-Purchase Factual Information in encouraging more Environmentally

Sustainable Product Purchase Decisions: Expert Interviews and a Rapid Evidence Assessment 1

Executive summary

A wide range of labels, accreditations, procurement tools and other information sources

are used to indicate to consumers the relative environmental sustainability of a product.

This is to inform decision-making and potentially encourage purchase of less

environmentally damaging products. However, given the range of approaches and

products that such information may be applied to, there is a need to bring together

evidence to assess and potentially improve its effectiveness. As such, this report was

commissioned to explore the existing evidence to address the following primary research

question:

What evidence is there about the effectiveness of providing factual information (including content, source

and format) on the environmental sustainability of a product in influencing consumer (individual and

organisational) buying decisions?

Secondary research questions related to other factors that have a role in influencing

consumers, including other product information and consumer characteristics.

Research protocol

A rapid evidence assessment (REA) methodology was used to identify research relating to

the primary research question. An REA is intended to be a systematic, but rapid review of

the literature and to offer an assessment of relevance and robustness of the extant, peer-

reviewed and grey literature. Whilst not intended to be as exhaustive as a systematic

review, an REA can nevertheless provide a comprehensive coverage of the literature

(within the time available) and provide conclusions that are weighted by the quality of the

available evidence. Interviews were conducted with experts in the field of labelling to

inform the development of the search protocol, and provide insight into key areas of

work.

The primary research question was operationalised by identifying the Population

(individuals and organisational consumers), the Intervention (provision of factual

information on the environmental sustainability of a product), the Comparison (no factual

information), and the Outcome (purchasing behaviour) i.e. the PICO1 elements of the

question.

Search terms relating to the PICO elements were generated and search strings used in

the literature databases Scopus and Web of Science, as well as the internet search engine,

Google (for grey literature). Using a formalised inclusion and exclusion criteria, an iterative

process of identifying relevant literature based on titles, abstracts and then full texts was

used to form an evidence base of literature. The evidence was then assessed for relevancy

and robustness and the findings extracted. Findings were synthesised to provide insight

into the primary and secondary research questions. Confidence statements for

converging findings were then given based on the amount and assessed quality of the

evidence (low, medium, or high). If findings diverged, then the influence is stated as

contested.

1 Population, Intervention, Comparison, and Outcome



Evidence characteristics

The evidence base for this REA was cumulatively large (72 sources were included);

however, given the heterogeneity of products and environmentally sustainable

information across the studies, the evidence was grouped into smaller, more comparable

sub-sets of evidence. Grouping was done first by product category, then within those

groups, by the category of sustainability information.

Studies on appliances2 were the most frequent in the evidence base, followed by cleaning

products/home chemical products. Energy efficiency and energy consumption were the

two most frequent environmentally sustainable information aspects tested.

Evidence synthesis

Overall, there is robust evidence that energy consumption information (particularly the

EU Energy Label) can influence purchase behaviour and intentions (although there is less

evidence for the Korean Energy Frontiers and China Energy Efficiency label and contested

evidence for ENERGY STAR). There is contested evidence that information on monetary

running costs for appliances instead of (or in addition to) energy consumption has a

positive impact.

For other environmentally sustainable aspects there is a wider range of products and

information3 explored, which means it is difficult to draw conclusions. However, across

the products, for environmentally sustainable aspects including carbon footprint, recycled

parts, organic and remanufactured there is some evidence that labelled products may be

preferred over unlabelled products, with a higher willingness to pay (WTP) for the labelled

products and lower WTP for the unlabelled. A small number of studies also explored

multiple aspects of environmental sustainability4 to assess the relative WTP for each one.

From these findings, it is suggested that which form of sustainability is most influential

may depend on the consumer’s understanding of what the label means; the more the

consumers understand what the label means, the more likely they are to be willing to pay

more.

Evidence for individuals as consumers is more prolific than the evidence available for

organisations as consumers. As organisations can frequently have strong buying power,

understanding the use of environmental information within their procurement strategies

will be important if organisations are to be persuaded to buy and use products which are

less environmentally harmful. What evidence there is in this REA suggests that some

organisations incorporate environmental performance of companies when procuring a

service, but this may be related to the nature of the organisation itself (e.g. they have

sustainability policies).

2 Fridges, freezers, washing machines and so on

3And several studies looked at multiple environmental impacts covered by an eco-label, or sustainability verified by a

stewardship label

4 For example, carbon footprint or water eco-toxicity



Price was often indicated, or found to be, an important factor in consumers’ decisions.

Price concerns may override environmental concern. However, in some instances the

WTP literature suggests that, to a point, consumers may be willing to pay a premium for

environmentally labelled products.

There was also some limited evidence that labels are less influential amongst older

consumers. In all cases, the influence of information is likely to depend on the product,

with the same information potentially having an influence on one product but not

another.

Conclusions and implications

Within the evidence base, a wide range of products has been explored in combination

with a wide range of environmentally sustainable information. In turn, this information is

presented in a range of different forms, content and framing. As such, giving an answer

to the primary research question that adequately captures the individual nature of

information and product combination is challenging. Furthermore, consumer

characteristics, such as: environmental concern; demographic factors; the importance

placed on price or brand, and understanding of what the label signifies, may each have a

bearing on how effective the information is at influencing the consumer’s decisions.

However, many studies show that providing information on environmental impact can

influence consumers’ buying decisions, at least in an experimental situation.

Further research is required using standardised, robust methodologies that enable

comparison across products and information types. In particular, further field trials or

experiments that involve the participant making a purchase (e.g., experimental auctions)

are required to have greater confidence in the evidence for labels, particularly non-energy

labels.



Contents

1.0 Introduction ................................................................................................. 6

2.0 Methodology ................................................................................................. 8

2.1 Development of Rapid Evidence Assessment protocol ............................... 8

2.2 Overview of the REA Protocol .................................................................... 8

2.3 Expert interviews ...................................................................................... 9

2.4 Call for evidence ..................................................................................... 10

3.0 Results ........................................................................................................ 10

3.1 Evidence base characteristics .................................................................. 11

3.1.1 Environmental sustainability information ...................................... 12

3.1.2 Products ...................................................................................... 16

3.1.3 Measures of influence (method) ................................................... 16

3.1.4 Intervention types ........................................................................ 17

3.1.5 Geographic distribution of studies ................................................ 18

3.1.6 Assessment scores ....................................................................... 18

3.2 Evidence synthesis .................................................................................. 19

3.2.1 Appliances.................................................................................... 20

3.2.2 Consumer electronics and ICT ....................................................... 24

3.2.3 Cleaning/ home chemical products and cosmetic products ............ 27

3.2.4 Automotive .................................................................................. 30

3.2.5 Buildings and construction ........................................................... 30

3.2.6 Paper and Wood Products ............................................................ 31

3.2.7 Textiles and clothing ..................................................................... 33

3.2.8 Procurement ................................................................................ 35

3.3 Summary of synthesis ............................................................................ 36

4.0 Conclusions and Implications ..................................................................... 38

4.1 Overall conclusions and recommendations for future research ............... 42

5.0 References .................................................................................................. 43

Figures

Figure 1 Environmentally sustainable information used in the evidence base .............. 12

Figure 2 Images of some of the labels investigated in the evidence .............................. 13

Figure 3 Products investigated in the evidence base .................................................... 16

Figure 4 Methods used in the evidence base ............................................................... 18

Figure 5 Relevance and robustness scores by product ................................................. 19

Tables

Table 1 Description of the evidence identification and selection .................................. 11

Table 2 Description of confidence statement classifications ......................................... 11

Table 3 Matrix of information type by product with indication influences ..................... 15



Acknowledgements

The authors would like to acknowledge the invaluable assistance of the stakeholders

who gave their time and expertise to this evidence review.



1.0 Introduction


are used to persuade buyers (individuals and organisations) to purchase products with

lower, negative environmental impact. In particular, labels are well established,

geographically widespread (used in both the developed and developing world), can cover

a wide range of sustainability considerations, and can be established by a range of

stakeholders (mainly environmental third-sector organisations, Governments and their

agencies). Labels cover a wide range of products (electrical appliances; food; vehicles;

buildings; services; textiles; packaging) and environmental aspects (energy use; carbon

footprint; sustainability; lifecycle impact; water use; reparability and durability). Further, a

recognition of the purchasing power of organisations, particularly national and local

government has resulted in the development of green procurement guides. These aim to

increase the uptake of products with lower environmental impact by providing criteria for

purchasers to use. Additional information sources include web sites which rate a range of

products on their environmental performance or expand upon information provided on

an existing label.

Various factors shape whether consumers pay attention to such information, how it is

processed and perceived, and whether it informs behaviour. For example, prior beliefs

act as a ‘filter’ for whether environmental claims are accepted and shape subsequent

attitudes and behaviour (e.g. Corner, Pidgeon, & Parkhill, 2012). Consumer choices may

be habitual, in which case information processing is minimal; or it may be more

deliberative, in which case information from different sources (e.g., friends, colleagues,

official sources) may be consulted and evaluated (Verplanken & Wood, 2006). The

information source, as well as content, format, and location, will be critical in this

evaluation by consumers, with trusted sources tending to be those that appear to have

integrity and competence (Clayton et al., 2015). Furthermore, environmental information

will be only one type of information which informs consumer decisions; other types

include financial, functional, social. Consequently, the impact of environmental

information on subsequent action is indirect and varies according to multiple

psychological and contextual factors. These factors are summarised in the conceptual

model included in the protocol (Appendix 1).

Defra and WRAP were interested in understanding the potential that providing objective,

factual information about the resource efficiency characteristics of a product has to drive

more sustainable purchasing, either on its own or in combination with other things.

They commissioned this research to access the existing body of research on

labelling/information provision through: a formal Rapid Evidence Assessment (REA) of the

academic and ‘grey’5 literature and interviews with experts in the field.

5 Literature informally or non-commercially published information that can be difficult to search for using conventional

searching techniques. Generally this is not published in formal academic journals. It may include conference papers and

reports published by public, private and third sector bodies.



Defra/NERC guidance6 states that an REA aims to provide an informed conclusion on the

volume and characteristics of an evidence base together with a synthesis of what that

evidence indicates following a critical appraisal of that evidence.

The primary question Defra posed for this research was:

“What evidence is there about the effectiveness of providing factual information (including

content, source and format) on the environmental sustainability of a product in influencing

consumer (individual and organisational) buying decisions?”

The secondary questions were:

“What other factors play a role in decisions, which have the most influence, and how do they

interact…?”, specifically:

a) What other product information (e.g. brand, type of product, price) and consumer

characteristics influence purchasing of environmentally sustainable products?

b) What factors have played a role in successful schemes?

c) What factors have played a role in unsuccessful schemes?

d) What, if anything, is required in addition to factual information to positively

influence purchase decisions?

The work has been undertaken by a team combining academic experts and independent

consultants with expertise in energy and environmental labelling. The team was as

follows:

◼ Fiona Brocklehurst, Ballarat Consulting; Lead Reviewer

◼ Dr. Colin Whittle, Department of Psychology Cardiff University, Evidence Analyst

◼ Catriona McAlister, Sea Green Tree, Reviewer (Sustainable Electronics / Resource

Efficiency)

◼ Prof. Lorraine Whitmarsh, Department of Psychology Cardiff University, Project

Director & Reviewer (Environmental Psychology)

The work was guided by a steering group formed of representatives of Defra and WRAP

whose members were:

◼ Jacks Guiness (initially, then Nathan Simmonds), Project manager, WRAP

◼ Keith James, WRAP

◼ Christian Reynolds, WRAP; Overall Assurer

◼ Debs Reynolds, Defra

◼ Leila McElvenney, Defra

◼ Ladislav Tvaruzek, Defra

◼ Maya De Souza, Defra

◼ Matt Stocks, Defra

The rest of this report describes the work as follow:

Section 2 – Methodology

Section 3 – Results

Section 4 – Implications

6 Collins, A.M., Coughlin, D., Miller, J., Kirk, S. (2015) The Production of Quick Scoping Reviews and Rapid Evidence Assessments: A

How to Guide



2.0 Methodology

2.1 Development of Rapid Evidence Assessment protocol

The REA protocol was developed in association with the Defra/WRAP steering group and

in line with the Defra/NERC guidance on evidence reviews7. It was designed to provide a

systematic and objective survey of the evidence, to be transparent and to minimise bias.

The initial protocol proposed by the project team were refined in the light of feedback

from the steering group, suggestions by the experts interviewed and trial database

literature searches.

Specifically, keywords for the literature search were developed based on the PICO8

elements of the primary research question. Synonyms, antonyms and conceptually

similar terms for these components were determined using the research team’s

knowledge and guidance from the experts who were interviewed as a component of the

first part of the project. Likewise, a list of existing environmental sustainability labels

(individually searched for) were generated through the same processes. The keywords

were developed in an iterative process of trialling and refining by the research team such

that the results returned from the search were optimised to provide a comprehensive

overview of the available evidence. The draft list was then reviewed by the steering group.

Inclusion and exclusion criteria for evidence were determined by the research team, in

conjunction with the Steering Group, based on the PICO components of the primary

research question and the initial trialling and refining of search terms. For example, it

was decided to include research published between the year 2000 and current date, with

no geographic restrictions as long as the publication was in English; research on market

impacts (as against direct consumer response) were excluded. The full details are in

Appendix 1.

The draft protocol, as formally agreed with the steering group is given in Appendix 1.

2.2 Overview of the REA protocol

The REA protocol consisted of several stages:

1. Evidence search

2. Search using agreed terms search academic databases Scopus and Web of

Science and the internet (using an online search engine; call for evidence from

the steering group, expert interviewees (see below) and wider stakeholders.

The searches took place in in September 2018.

3. Screening search results

Screen search results for relevance to research topic undertaken in two stages:

firstly, on the paper or report title; secondly by the content of the abstract or

executive summary

7 Ibid.

8 Population, Impact, Comparator and Outcome



4. Extracting the evidence

Extract evidence extracted from the full paper or report text using a standard

form which captured: the details of the source; the nature of the study (eg

quantitative observation – such as a survey or a quantitative experiment such as

a choice experiment, the population studied) and the results (in terms of the

REA’s primary and secondary questions).

Rate each piece of selected evidence for robustness and relevance against

pre-determined criteria in the protocol and combine the scores to give an overall

confidence categorisation.

(Some further evidence was rejected at this stage as being irrelevant, based on

the full text or if found to be a duplicate.)

5. Synthesising the evidence

Review the evidence to answer the research questions and report on the

adequacy of the evidence base: describe the volume and characteristics of the

evidence base; describe what the evidence indicates; indicate the implications.

(Some further evidence was excluded at this stage , based on a more detailed

reading of the full text or if found to be a duplicate.)

These stages are described in detail in the protocol in the Appendix 1 and the results are

given below.

The protocol was refined in the course of its application. For example, more exclusions

were added to the search terms and some suggested search keywords were found to be

too broadly used (for example “bio”) and had to be excluded. A description of the

adaptations of the protocol are given in Appendix 2.

The greatest challenge in this stage of the process was making the search for ‘grey’

literature systematic; some sources were identified via the steering group, and a wider

group of stakeholders (via interviews and a call for evidence – see below). However, it was

essential for the completeness and objectivity of the REA that a systematic search was

made via an online search engine. It was found that the search syntax used in the search

of academic databases was not applicable in online search engines - this had to be

adapted. Professional librarians and experienced stakeholders were consulted as to how

best to do this.

2.3 Expert interviews

The interviews were intended to overcome the risk of publication bias by identifying:

◼ results from studies which do not find effects or impacts, and therefore are less likely

to be published; and

◼ recently completed or ongoing research

They also offered the opportunity to get additional suggestions on the development of

the protocol.

Interviewees were identified from amongst the research team and steering group’s

contacts to represent experts in the field of consumer behaviour, labelling, resource

efficiency and sustainability and reflecting a balance of academics (including different



disciplines), industry, non-governmental and policy representatives. In total, ten

interviewees agreed to participate.

Interviews took place by telephone, lasting a maximum of one hour. They were conducted

using a set of questions (Appendix 3) derived from the research objectives. These included

questions about the interviewees’ own work or expertise in sustainable information

provision (e.g. labelling), suggestions for literature that should be included in the review

and interviewees’ views on and responses to the primary and secondary research

questions. Answers were recorded by interviewers who took detailed notes during the call

on a standardised template.

Interviewees’ suggestions for literature were included in the main REA (screening,

extraction and synthesis). Interviewees’ views relating to the research questions are

presented in Appendix 4.

2.4 Call for evidence

The experts interviewed reinforced the project team’s initial view that a call for evidence

would be useful to extend the pool of evidence gathered by the review, so this was

undertaken. A text was agreed with the steering group and sent to contacts suggested by

the experts and those known to the team and the steering group. The call included asking

newsletters, associations and networks to publicise the call, as well as using social media.

The additional sources which were suggested in response were included in the REA.

3.0 Results

The flow of evidence through each stage of the evidence identification and selection

process is shown in the Table 1. A total of 72 pieces of evidence were included in the

synthesis. In this section, the characteristics of the evidence base will be described first.

Then, a synthesis of the findings from the evidence base will be reported. Throughout the

synthesis, confidence statements will be allocated to the conclusions. The confidence

statements (see Table 1) are based on the amount of evidence and the assessment scores

the evidence achieved. As such, confidence can be either High, Medium, Low or

Contested. These statements are only provided for the primary research question

evidence.



Source of

evidence

Search of

academic

databases

Online

search

Stakeholder proposals

(steering group, expert

interviewees, call for

evidence)

Total

Number at

each stage

Evidence

search

5315 NA9 NA >5000

Initial

screening

492 100 136 706

Screened

evidence

165 27 63 252

Evidence

extraction

68 9 30 107

Included in

synthesis

72

Table 1 Description of the evidence identification and selection

Class Description

High Evidence from several studies assessed as ≥6 and 1 or more studies

assessed as ≥7 10

Medium Evidence from one or more studies that have been assessed as ≥6

Low Evidence from a small number of studies or studies assessed all of which

assessed as <611

Contested Evidence that differs in its conclusions (present the assessment for each

study/evidence)

Table 2 Description of confidence statement classifications

3.1 Evidence base characteristics

Overall, the evidence base consisted of 72 pieces of evidence. Although there can be no

expectations or standards for the number of pieces of evidence in an REA, 72 might be

considered relatively large. However, this overall size may be indicative of the wide range

of environmental sustainability information that has been explored as well as the range

of products. Consequently, although a large number cumulatively, the numbers decrease

once the evidence is grouped by product or by information type. That is, though seemingly

large, the evidence base is heterogeneous in nature. To describe the evidence

characteristics as fully as possible, a number of different groupings and matrices have

been used.

9Millions of results were brought up by each set of search terms

10 This was changed from the draft protocol to reflect the fact that we allowed non-integer scores for robustness and relevance

and therefore scores of between 6 and 9 were possible. Therefore, a score of 7 was possible.

11 This was changed from the draft protocol so that low categorisations were distinct from medium



3.1.1 Environmental sustainability information

As shown in Figure 1, the most consistent type of environmental sustainability

information found within the evidence was related to the energy efficiency and energy

consumption of a product. Although, cumulatively, there were more studies that

investigated non-energy related information, these studies are more diverse in respect to

the information content conveyed, as opposed to the energy studies which were more

consistent in using an energy efficiency rating, kilowatt hours (kWh) and/or monetary

running costs to convey the energy consumption of the product. It should be noted that

for existing labels, we classified them by both the specific label and the information the

label gives, hence the greater number of information types than evidence.

Figure 1 Environmentally sustainable information used in the evidence base



Figure 2 shows the form and content of some of the labels that were investigated in the

evidence.

Figure 2 Images of some of the labels investigated in the evidence

In addition to consistency in the information content, the energy consumption evidence

also shows more consistency in their presentation form and product. For instance, as

shown in Table 3, the energy consumption was predominantly explored in relation to

appliances, and heating, ventilation and air-conditioning (HVAC). This might be expected

due to the international adoption of energy efficiency standards for appliances. Indeed,

the energy literature has a far larger proportion of existing labels compared to study-



specific labels (i.e. labels or information that was generated by the researchers for their

study’s purposes). This is likely to represent the relatively longstanding nature of some of

the energy labels.

The proportion of existing labels to study-specific labels is reversed for the non-energy

evidence, which has a range of environmental sustainability information being tested (see

Table 3).

Table 3 indicates the number of studies and the effect they found for the information type

by the product category. The indication of effect has been simplified for tabulation and so

may not fully represent each study and the synthesis provides more detailed discussion

on the different effects. However, the table does show the areas that have been

investigated and the average findings. Note that some studies investigated multiple

products and so the numbers in Table 3 do not equal the evidence base number.

WRAP - The Effectiveness of Providing Pre-Purchase Factual Information in encouraging more Environmentally Sustainable Product Purchase Decisions: Expert Interviews

and a Rapid Evidence Assessment 15

Table 3 Matrix of information type by product with indication influences

EU energy label 1 2 8

Energy Star 1 2 1

Energy Rating 1 1

EnergGuide 1 2

Euro Topten 1 1 1

Energy Frontier 1 1

China Energy Label 1

Nordic Swan 1 1

Building energy performance (incl. BEAM, BER and EPC) 1 2

Green Seal 1

Wood certification (incl. Swiss Quality label and FSC) 5

Energy consumption (kWh) 4 2 12 1 1 2 1 1

Energy efficiency 4 2 14 1 1 4 1

Monetary running costs 1 3 5 2

Carbon footprint/emissions 1 2 1 1 1 1 1

Lifespan 1 1 1 1

Recycled/ reclaimed materials 1 1 1 2 1 1

Remanufactured/refurbished 1

Organic 1

Environmental impacts (incl. water and resource depletion)1 2 1 2 1 1 4 1 4 1 2 1

Unspecified Eco/Green/Environmentally friendly 1 1 1 1 1 1 1 4 5 1 3 1 1 1 1

1 1 studies with positive impact

X 1 studies with unclear results

0 1 studies with no impact

HV

AC

Textiles and

cloth

ing

Clean

ing / h

om

e

chem

ical pro

du

cts

Co

smetic an

d

ph

arma p

rod

ucts

ICT co

mp

on

ents

and

pro

du

cts

Co

nsu

mer

electron

ics

Large ho

useh

old

app

liances

Small h

ou

seho

ld

app

liances

Lightin

g

Oth

er misc o

r

pro

du

ct no

t

specified

Packagin

g

Pap

er and

wo

od

pro

du

cts

Bu

ildin

gs and

con

structio

n

Au

tom

otive



3.1.2 Products

The range of products and their frequency in the evidence base is shown in Figure 3.

Appliances are the best represented, followed by cleaning/home cleaning products. Some

products appeared only once in the evidence base. The frequency of studies investigating

appliances is related to the high level of studies investigating energy consumption. In

contrast, the high frequency of clearing/home products may be due to researchers

intending to select products which are regularly purchased by a large number of

consumers and are, therefore, familiar to most consumers.

Figure 3 Products investigated in the evidence base

3.1.3 Measures of influence (method)

As shown in Figure 4, a range of measures has been used to assess the influence of the

environmental sustainability information on participant/consumer behaviour. Actual

purchase behaviour is the least frequent measure, whilst purchase intentions, willingness

to pay (WTP) and choice of product (indicating product preference) were the highest.

Studies which focused on intentions to purchase or choice preference between two or

more products were frequently used as the outcome to assess the influence of consumer

information. In addition, many of these studies also measured other factors to test



hypothesised relationships, mediations and moderations between the factors and

intentions/choice.

Several studies measured self-reported past-purchases; that is, those which asked people

if they had bought a product recently, if that product had a label and if so, did it influence

them. This category also includes studies which asked people if they recalled using a

label/information when purchasing a product in the past. These studies typically

presented descriptive data in the form of percentage of people asked.

Willingness to pay (WTP) was measured in multiple ways. Frequently, participants were

asked how much extra (premium) they would be willing to pay for a product that was

associated with environmentally sustainable information. This was then indicated either

as a monetary amount or percentage increase in price, in response to either an open-

ended question or multiple-choice options. These results are distinct from WTP measured

in a choice experiment - in which the amount participants would be WTP for the product

is statistically inferred based on the product selection across multiple choices.

3.1.4 Intervention types

A large number of studies in the evidence base used an experimental design to explore

the effects of different information. Although there was not always a control group, the

experimental designs typically enabled the different effects of the information content, or

no information, on participants’ choices, preferences, intentions, or purchases.

A brief (and certainly not comprehensive) explanation of choice experiments will be given

to aid the understanding of the results. The choice experiment methodology involves

presenting participants with products that are given a number of attributes. These

attributes are then given discrete levels. For example, an appliance may be given an

attribute of “colour” and that attribute given three levels; silver, black or white. The

attributes the product have stays the same, but the level of the attribute is randomised.

As such, participants are shown two or more products with comparable attributes, but

the levels of those attributes will be different (e.g. a silver fridge vs a white fridge). The

participant then compares the products and selects the one they would prefer. This

design enables researchers to statistically infer the attribute that had the most influence

over the participants’ product choices (e.g. if colour was most important and if so, what

colour). Within this evidence base, it was typical to present a product with at least one

attribute which related to environmental sustainability information/labelling.



Figure 4 Methods used in the evidence base

3.1.5 Geographic distribution of studies

There was a requirement that the publication was written in English but the search was

not restricted geographically and evidence for studies conducted in several different

countries or regions were found. The largest proportion of studies were in the EU with

several including studies in several Member States or associated countries, perhaps

representing the high proportion of EU Energy Label studies. A proportion of studies were

conducted in the US (particularly ENERGY STAR studies), whereas a smaller proportion

were conducted in China and South Korea.

3.1.6 Assessment scores12

Average assessment scores by product are indicated in Figure 5. As a large amount of the

evidence base is composed of peer-reviewed literature, the frequency of evidence

achieving the maximum of three for robustness was high. However, due to the

assessment criteria only awarding a three for relevance if the study was a field trial, of

which there are few, only a small number of studies achieved the maximum nine on the

assessment.

12 The criteria used to assign relevance and robustness scores are defined in Annexes B and C of Appendix 1, the REA protocol



Figure 5 Relevance and robustness scores by product

3.2 Evidence synthesis

For presentation and discussion, the evidence is grouped by product type under the broad

product categories of appliances (including heating and cooling), consumer electronics,

cleaning/home chemical products and cosmetic products, automotive, textiles and

clothing, buildings and construction, and paper and wood products. Where there is

sufficient evidence, the evidence is further grouped in to those that have the same

environmental sustainability information. This was done to facilitate the synthesis of the

evidence and to highlight converging and diverging findings. As highlighted in the

evidence base characteristics section, some products have been investigated in only one

or two studies13, whereas others have been investigated more frequently. Likewise, as

some studies investigated more than one product, some evidence is cited in more than

one section.

The findings have been split into those that relate to the primary research question14 and

those that relate to the secondary research questions. The available evidence for both

13 in the evidence base

14 The primary research question was: What evidence is there about the effectiveness of providing factual information

(including content, source and format) on the environmental sustainability of a product in influencing consumer

(individual and organisational) buying decisions?



primary and secondary research questions varies with product type, with secondary

evidence not extracted for some product types.

3.2.1 Appliances

Primary research question; appliances

Appliance confidence statements:

• There is evidence that EU Energy Label positively influences the purchase, choice,

or intentions, towards more energy efficient appliances (confidence = high).

• There is contested evidence for the influence of ENERGY STAR on consumer

behaviour.

• There is contested evidence for the addition of monetary running costs to the EU

Energy Label.

• There is contested evidence for the influence of monetary running costs

compared to energy consumption on consumer behaviour.

• There is evidence that carbon footprint information, in conjunction with energy

consumption information, positively influences willingness to pay for washing

machines. (confidence = medium).

• There is evidence that environmental impacts information (carbon footprint,

water use, eco-toxicity, and resource depletion), in conjunction with energy

consumption information, positively influences willingness to pay for washing

machines. (confidence = medium).

• There is evidence that product lifespan information increases consumer

preference for the labelled appliance (confidence = medium).

When surveyed, most consumers say they use energy labels when purchasing appliances.

For instance, 88% of 4,000 Australians reported using an energy label (which included the

Australian Energy Rating, Gas Energy Rating, or Water Conservation Rating labels and

ENERGY STAR) and 75% indicated the label is very important in their appliance purchasing

process (page 5, ArtcraftResearch, 2005). However, these types of studies, which ask if

people have used labels when making purchases, may give an over-optimistic picture of

how much people are influenced by labels. For instance, Feldman and Tannenbaum

(2000) specifically looked at USA consumers who had recently bought either a refrigerator

or a clothes washer (approx. sample size of 560 & 240, respectively). In their sample, only

16% for refrigerators and 7% for clothes washers both recalled the ENERGY STAR logo

being present on their appliance and reported being influenced by it.

The influence of the EU Energy Label on appliance purchases has been explored most

frequently out of the existing labels in the evidence base. Overall, there is strong evidence

that the presence of an EU Energy Label on a large appliance influences - or is related to

– selection of the more energy efficient product. For instance, the majority of respondents

in Greece (85% of 596) self-reported that the EU Energy Label had influenced their

purchase of refrigerators and the majority of respondents in Spain (72% of 500) reported

it had influenced their purchase of washing machines (Foudi, de Ayala, López, & Galarraga,

2018). Furthermore, WTP increased with higher grades of energy efficiency (indicated on

the label), with WTP increasing by 696 CHF (£547) for an A graded washing machine



compared to a C graded washing machine (347 CHF for B to A) (Langley et al., 2012;

Sammer & Wüstenhagen, 2006). Critically, in an experimental field trial, it was found that,

compared to no label, having an EU label increased the purchase of more energy efficient

vacuum cleaners, tumble dryers, and fridge freezers (Stadelmann & Schubert, 2018). As

such, overall, there is strong evidence that the presence of an EU Energy Label on a large

appliance influences - or is related to - more frequent choosing the more efficient product.

The US ENERGY STAR label has not been explored as frequently as the EU Energy Label

within the evidence base; there is some evidence for an influence of the ENERGY STAR

label on consumers. In a field trial, telesales provided some customers with information

on the energy efficiency and environmental benefits of ENERGY STAR water heaters. This

did not have a significant influence on purchases compared to when the telesales people

did not provide the benefits information (Allcott & Sweeney, 2017). However, this study

had multiple confounds as the salespeople varied in their delivery of the information.

These variations perhaps highlight the difficulty of conveying environmental sustainability

information to customers in a real-world setting, and make the findings difficult to

interpret or generalise.

In contrast, though, an analysis of transactions from a US appliance retailer, Houde (2018),

found that the ENERGY STAR label had a positive association with WTP for a full-size

refrigerator. The WTP also increased with the consumers’ income with a WTP of US $30 in

the low-income tertile, US $44.60 in the medium-income tertile and US $56.90 in the high-

income tertile. A refrigerator with the ENERGY STAR label (compared to no label) was also

found to be preferred and have a higher WTP of between US $249.82 (£195.93) and US

$348.30 (£273.95) compared to no label (estimations varied with model used) (Ward,

Clark, Jensen, Yen, & Russell, 2011).

The Australian Energy Rating label has had few studies explore its influence that were

selected in the evidence base for the REA. A field trial in an Australian online store found

that there was no statistically significant effects of the Energy Rating Label or of their own

running costs label on purchases of vented dryers, fridges or washing machines

compared to when there was no label (BETA, 2018). However, the observed, non-

statistically-significant changes did suggest a positive effect of labels – but there was no

statistically significant difference between the effectiveness of the two labels.

A newer energy label is the South Korean Energy Frontier label. The only study15 to test it

offers medium strength evidence that the presence of the label was associated with

greater preference and an increased WTP for refrigerators as the energy efficiency grade

(indicated on the label) increased (Jeong & Kim, 2015). A single study16 also explored the

China Energy Efficiency Label and found that higher ratings were associated with a higher

WTP for air conditioners and refrigerators (Shen & Saijo, 2009). Similarly, a WTP of

US$67.60 (£52.85) was found for an increase from a (study-specific) 3 star energy

efficiency rating to a 5 star rating on air conditioners in India (Jain, Rao, & Patwardhan,

2018).





Only one study17 (Barthel, Kaselofsky, & Madry, 2015) explored the provision of energy

information not in a label form. In a follow-up survey (n=399), it was found that 82% of

visitors to the Euro Topten website (website to provide information the most energy

efficient products on sale in a given country) bought one or more products listed on the

website (household appliance or a lighting device). These results cannot be considered

representative of all the visitors to the website, as respondents to the follow-up survey

will be highly motivated participants.

The EU Energy Label in its current form (displaying an energy efficiency rating and annual

energy consumption as kW/h) was often used as the control label in the large appliance

studies, with the relative effectiveness of adding monetary running costs to the EU Energy

Label being tested. The evidence from the experimental field trials is contested, with

either no significant effect found for the addition of running costs or an effect found, but

only when in conjunction with other factors (DECC, 2014; Kallbekken, Sælen, &

Hermansen, 2013; Stadelmann & Schubert, 2018). For instance, compared to just the EU

Energy Label, the addition of lifetime running costs to the EU Energy Label did not

significantly increase purchases of the more energy efficient vacuum cleaners, tumble

dryers, fridge freezers, or washing machines (DECC, 2014; Kallbekken et al., 2013;

Stadelmann & Schubert, 2018). For tumble dryers, there was a significant effect of adding

the running costs, however, it was only when the labels were combined with staff sales

training and because of the tumble dryer’s higher running costs (relative to the non-

significant fridge-freezer; (Kallbekken et al., 2013). Likewise, DECC (2014), also found a

significant effect of adding running costs, but only for the washer-dryer, where the high

running costs (compared to the washing machine and tumble dryers) may have made the

information more salient to the customer.

In contrast, studies using experimental surveys suggest that the addition of running costs

to the Energy Label or providing running costs alone, are more effective than the EU

Energy Label on its own (Andor, Gerster, & Sommer, 2016; Blasch, Filippini, & Kumar,

2017). For instance, compared to a simplified version of the EU Energy Label (only the

energy consumption information), the addition of annual running costs significantly

increased the participants’ choice of more efficient refrigerator (Andor et al., 2016).

Similarly, for lightbulbs and refrigerators, displaying the annual energy consumption on

the EU Energy Label as a monetary cost compared to a physical unit (kWh, as is standard),

led to a greater likelihood that the most cost-efficient appliance was chosen (Blasch et al.,

2017).

Further studies compared energy consumption information with monetary running costs.

Using variations of the EnergyGuide label, it was found in the USA that the monetary

savings information had the strongest influence on water heater choices, followed by the

amount of physical energy an appliance used, followed by information on CO2 emissions

(Newell & Siikamäki, 2014). In contrast another US study found that, providing information

(in monetary terms) on how much energy could be saved by each washing machine did

not have a significant effect on participant choices (compared to no monetary energy

saving information), whereas an study-specific energy efficiency score was associated




with choosing the more energy efficient washing machine; (Niederberger & Champniss,

2017).

Three studies (two conducted by Langley et al., 2012) in the evidence base investigated

the effect of other forms of environmental sustainability information, rather than just

energy consumption. In a large cross-European study, (including UK, France, Germany,

and Italy), Langley et al. (2012) found that, compared to the current EU Energy Label, bids

in an experimental auction were higher for washing machines (average of €3.75) that had

a modified EU label that also displayed the products’ carbon footprint. The same effect

was found for adding environmental impacts (including carbon footprint, water use, eco-

toxicity and resource depletion), although the increase was smaller (€2.16). For all the

labels, the level of efficiency indicated by the label had a significant effect on bids as well,

with bids for higher efficiency washing machines being an average €2.99 higher than for

lower efficiency versions. In contrast, there were no significant differences in bids for

lightbulbs18. A choice experiment using the same labels supported their experimental

auction findings, with a WTP an average of 40% more for a washing machine with the

“energy and carbon footprint label”.

A further, large scale, European experimental survey tested the effect of lifespan

information. It was found that lifespan labelling influenced purchasing decisions in favour

of products with longer lifespans. Across the tested products (which included washing

machines, vacuum cleaners and coffee makers), products with a label showing a longer

lifespan than the competing products were chosen an average of 13.8% more (Jahnich,

Boulbry, & Dupre, 2016).

Secondary research question; appliances

Which other product characteristics shape decisions: Price is commonly found to be one

of the most important factors that consumers take into account when they are buying an

appliance. For instance, in several studies in the evidence base, price was found to be

most influential (Consumer Focus, 2012; Goucher-Lambert & Cagan, 2015; S. L. Heinzle &

Wüstenhagen, 2012).

Which audience factors are relevant: Age and gender have been found to influence

purchase decisions in a number of studies. For age, there is some evidence that the

influence of energy and lifespan labels decreases with age (Jahnich et al., 2016; Ward et

al., 2011). However, gender differences may exist for different labels; preference for

refrigerators with the ENERGY STAR label was higher among males than females (Ward et

al., 2011). However, in a separate study females were more likely than males to base their

choice of appliances on the lifespan label (Jahnich et al., 2016).

Understanding of the labels is also highlighted by some studies within the appliance

evidence. For instance, greater understanding of labels was associated with choosing the

more energy efficient appliances (Langley et al., 2012). Similarly, more general energy

18 The authors speculate that “the lower stakes associated with light bulbs in the bidding experiment, and the need to input bids which included decimal points, may have led to more manual errors creating noise in the light bulb bid data. This has resulted in observations for the light bulbs not being as clear as those for the washing machines and televisions.”



literacy and investment literacy was associated with choosing the more efficient appliance

(as indicated by the EU Energy Label; Blasch et al., 2017). Equally, a lack of information or

a lack of understanding of the label may prevent people being able to choose the most

energy efficient appliance (Consumer Focus, 2012; Nguyen, Pham, Nhan Nguyen, Chu, &

Pham, 2018).

Which informational characteristics are most/least effective: The design of the label was

compared in a couple of the studies. Variations of the EnergyGuide label design had

similar influences on product choice (Egan, Payne, & Thorne, 2000) and a simple table of

the information was as effective as the EU Energy Label (Waechter, Sütterlin, & Siegrist,

2015). Likewise, all tested variations of a study-specific, alphabetic or numeric energy

scale, lead to statistically higher bids for the more efficient washing machine (London

Economics, 2014). However, a comparison of the EU Energy Label with the A-G scale was

associated with higher WTP then the A+++-D scale (S. L. Heinzle & Wüstenhagen, 2012).

Furthermore, providing an energy rating label on air conditioners increased intention to

purchase, compared to just plain text describing the level of efficiency (Gu, Morrison, &

Yu, 2009). Therefore, it is not clear from the evidence base what the design characteristics

for more effective labels are. However, having energy efficiency information that is

consistent and comparable between two competing products could be important (Zhou

& Bukenya, 2016).

There was some indication that labels can have unintended consequences on consumer

behaviour. For instance, one study (Stadelmann & Schubert, 2018) found that EU Energy

Labels (and EU Energy Labels with running costs) led to an increased purchase of larger

freezers. Therefore, although the more efficient freezer was purchased when it had a

label, it was also larger and so had an equivalent energy consumption to the smaller, less

efficient freezers. As such, energy consumption would not have been reduced.

Participants may also associate labels with higher quality, not just efficiency. In two WTP

studies, the indicated, expected monetary savings from the higher efficiency appliance

were lower than the amounts participants were WTP for the higher efficiency (Sammer &

Wüstenhagen, 2006; Ward et al., 2011). Sammer and Wüstenhagen (2006) suggest that

this could be due to participants inferring other positive qualities about a more efficient

product.

Other things of note are that having regionally correct running cost estimates on the US

EnergyGuide label (cost calculated based on customers’ US state) led to more frequent

selection of the more energy efficient air conditioners compared to national average

running costs (Davis & Metcalf, 2016). Also, the amount a product is used was suggested

to be an important factor in one study as there was a higher willingness to pay for energy

efficiency of refrigerators (continuous use) compared to air conditioners (seasonal use)

(Shen & Saijo, 2009).

3.2.2 Consumer electronics and ICT

Relatively few studies in the evidence base investigate consumer electronics and/or ICT.

Both the influence of energy consumption information and environmental impact

information has been investigated.



Primary research question; consumer electronics and ICT

Consumer electronics and ICT confidence statements:

◼ There is evidence for an influence of energy consumption (kWh) information on the

WTP for televisions (confidence = medium).

◼ There is contested evidence for the influence for monetary running costs on choice of

televisions.

◼ There is evidence that an energy saving label and an eco-label positively influence

WTP for a laptop (confidence = medium).

◼ There is evidence for the positive influence of combined energy and carbon footprint

information on WTP for televisions (confidence = medium).

◼ There is evidence for the positive influence of combined energy environmental

impacts information (carbon footprint, water use, eco-toxicity, and resource

depletion) information on WTP for televisions (confidence = medium).

◼ There is evidence that lifespan information does not influence television preference

(confidence = medium).

◼ There is evidence that lifespan information does influence printer and mobile phone

preference (confidence = medium).

◼ There is evidence that recycled materials label positively influences WTP for a single-

use camera (confidence = medium).

◼ There is evidence that a remanufactured label positively influences WTP for a single-

use camera (once environmental benefits are explained) (confidence = medium).

◼ There is evidence that a no-label, single-use camera will have a lower WTP than a

labelled recycled or remanufactured single-use camera (confidence = medium).

In terms of energy consumption, there is not a lot of evidence in the evidence base. For

televisions, one study found that participants19 were willing to pay more for the more

efficient television, indicated by either the monetary running cost or energy consumption.

However, the WTP for annual energy operating costs (€353.97) and annual energy

consumption in Watts (€481.22), were not as high as the lifetime energy operating costs

(€641.60) (S. L. Heinzle, 2012). In addition in another study, across a number of study-

specific, energy efficiency labels (with variations of alphabetic or numeric scales), there

were statistically higher bids on the televisions with the higher efficiency scores (although,

this was only approximately €4 higher) (London Economics, 2014). In contrast to the WTP

studies, a field trial in an online store found that there was no statistically significant

effects of the Australian Energy Rating Label or of running costs, on smart television

purchases compared to when there was no label20 (BETA, 2018).

For laptops21, there was one study in the evidence base, which found a laptop with an

energy-saving label was preferred to a laptop with no label and had a WTP of 13.9-18.2%.

The energy-saving label also had a higher WTP than an Eco-label (8.9-10.5%), although the

eco-label did have significant effect on laptop choice, compared to a laptop with no label

(Jeong & Kim, 2015).

19 in Germany

20 This was also true for appliances – see previous section

21 study in Korea



In terms of other environmental sustainability impacts, there are two studies in the

evidence base. Compared to the EU Energy Label, an EU Energy Label with additional

carbon footprint information led to a WTP an average of 37% more for a television and an

average minimum premium of €64. Similar results were found for additional carbon

footprint, water use, eco-toxicity and resource depletion information (Langley et al., 2012).

In contrast, in a large experimental survey, a lifespan label had no significant effect on

television choice (Jahnich et al., 2016),22 but there was a significant effect for printers and

mobile phones.

Exploring the environmental impacts of the materials a product is made from, Michaud

and Llerena (2011) found that, in an experimental auction23, the WTP for a single-use

camera made from refurbished parts was lower than the WTP for a camera made from

recycled materials and the WTP for a camera made from all new materials. However,

following an explanation of the environmental benefits of the remanufactured and

recycled cameras and the lack of benefits of the new material cameras, the WTP for the

remanufactured camera increased, whilst the willingness to pay for the new materials

camera decreased. The WTP for the recycled camera remained similar. As such, explaining

the environmental credentials of cameras made from refurbished parts did not increase

the amount people were willing to pay for the camera, but rather decreased the amount

they were willing to pay for the conventional, non-refurbished camera.

Secondary research question; consumer electronics and ICT

Which audience factors are relevant: In one study, the importance of understanding labels

on consumer decision-making was demonstrated, as was the significance of non-labelled

products being compared to labelled products. As outlined in the primary evidence, WTP

of the single-use camera labelled as remanufactured increased once the environmental

benefits of remanufacturing was explained. At the same time, the WTP for a non-labelled,

conventional camera significantly reduced once participants understood the benefits of

the other recycled or remanufactured labelled cameras. As such, it appears that

knowledge of the label/environmental credentials associated with the label are important

in determining WTP (Michaud & Llerena, 2011). Furthermore, not only did WTP decrease

for the conventional camera, but also the number of participants who bid for the

conventional camera decreased. Those who boycotted bidding for the conventional

camera reported doing so because they did not want to purchase the most polluting

product when a more environmentally friendly substitute was available (Michaud &

Llerena, 2011).

Which informational characteristics are most/least effective: The importance of the framing

of the message was indicated in one study24. Lupiáñez-Villanueva, Tornese, Giuseppe, and

Gaskell (2018) found that, for laptops, negatively framed messages about the

22 The authors suggest that the motivations when buying TVs might be an explanation for this; alternatively the very close

similarity between the range of available televisions meant that participants did not pay much attention to the attributes of these

very similar products.

23 in France

24 in a number of EU countries



consequences of harming the environment for the countries’ children significantly

discouraged product choice, whilst a positively framed message did not. Likewise, a

negative framed message focusing on health consequences of environmental harm,

discouraged product selection. This may suggest that negative framing has a stronger

influence than positive framing.

Combining a label with written information may be more influential than either one alone.

For batteries, Tang, Fryxell, and Chow (2004) found25 that a combination of a label and

written information about the environmental sustainability of batteries had the greatest

influence. However, the label only and the written information only also lead to higher

purchases than the batteries with no information.

3.2.3 Cleaning/ home chemical products and cosmetic products

Primary research question; Cleaning/home chemical products and cosmetic products

Confidence statements for Cleaning/home chemical products:

◼ There is evidence of the positive influence of environmental claims on intentions to

purchase laundry detergent (confidence = high).

◼ There is evidence that carbon emission information and green advertising do not

influence intentions to purchase insecticide (confidence = medium).

◼ There is evidence that an ecolabel and additional, suggested environmental benefits

(e.g. natural) positively influence selection of shampoo (confidence = low).

Labels that indicate the lower environmental impacts of cleaning and home chemical

products have been relatively well investigated, with laundry detergent being the most

frequently studied. Five studies investigated intentions to purchase laundry detergents.

Each used a study specific label or environmental information, however, each one used

an experimental design (label vs no label) and found an effect: of claiming the product is

“environmentally friendly” (Brach, Walsh, & Shaw, 2018; Pancer, McShane, & Noseworthy,

2017; Spack, Board, Crighton, Kostka, & Ivory, 2012), that the bottle is made out of recycled

material (Magnier & Schoormans, 2015), or that the detergent was made using less

resources (Cho, 2015). Whilst only intention based evidence, they provide strong evidence

for the influence of environmental information on purchase intentions for laundry

detergent. Similarly, Tang et al. (2004) found26 that both a label and written information

about the sustainability of a hairspray separately led to higher purchases in an

experimental setting compared to no information. Furthermore, the combination of the

label and the written information led to the highest purchases.

Y. Bernard, Bertrandias, & Elgaaied-Gambier, 2015, found that the perceived

environmental harmfulness of washing-up liquid - indicated by a study-specific label with

either a red traffic-light (environmentally harmful) or green traffic-light (environmentally

friendly) - lead participants to select the environmentally friendly product as the perceived

25 in Hong King

26 in Hong Kong



harmfulness was lower. This effect was moderated by environmental concern and price

(see the secondary findings below).

Exploring an existing label in a European survey of ten countries (including UK, Poland,

Czech Republic and Denmark), it was found that, on average, across the countries, 73% of

participants chose a more expensive shampoo (2.8% premium) that had a Green Dot

license symbol (indicating recycled packaging), ecolabel and a “natural shampoo” claim

over a cheaper shampoo that only had the Green Dot. There were cross-national

differences, however, only The Netherlands had a majority (51%) that selected the

cheaper shampoo (GFK, 2014).

For insecticide, two studies suggest that providing either information on the lifecycle

carbon emissions (Stokes & Turri, 2015) or an advert promoting a companies’ “green

message” (Nyilasy, Gangadharbatla, & Paladino, 2014)27 does not influence consumer

purchase intentions.

Overall, the strongest evidence indicates that information on the environmental

credentials of detergent can positively influence intentions to purchase. However,

evidence for its effect on WTP for detergent and purchase intentions of insecticide is

weaker.

Secondary research question; cleaning/home chemical products and cosmetic products

Which audience factors are relevant: Understanding and familiarity with labels were again

found to be important for the effect of labels in the cleaning/home chemical products.

Rather than comparing the effect of environmental sustainability information versus no

environmental sustainability information, three studies explored the relationship

between characteristics of the consumer and their past purchases. In these studies,

objective knowledge of environmental labels (measured differently in each study) was

found to be positively correlated to self-reported purchasing of fast-moving-consumer-

goods (e.g. toiletries) which have the label (Palomo, Martínez, & Bosch, 2015) and cleaning

products (Testa, Iraldo, Vaccari, & Ferrari, 2015). Relatedly, Y. Bernard et al. (2015) found

that self-reported familiarity with environmental information on products moderated the

effect of the negative environmental message. As such, the intentions of those who were

unfamiliar with environmental information were less effected by the negative information

than those who were more familiar. These studies suggest that either positive or negative

information is less effective if the consumer is less knowledgeable or familiar with labels.

In contrast to understanding of labels, in one study, age and education had no

relationship with past purchasing behaviour for ecological cleaning products. Women

were more likely to self-report having purchased ecological cleaning products than men.

The same study also showed that placing greater importance on brand had a negative

correlation with past purchases of eco-friendly cleaning products (Testa et al., 2015).

When looking at the effect of environmental concern or involvement as a moderator,

those who score higher subsequently indicated greater intentions to purchase the

27 both in USA



labelled products (Cho, 2015; Magnier & Schoormans, 2015). Furthermore, environmental

concern positively moderated the effect of perceived harm on choice of the

environmentally friendly product (Y. Bernard et al., 2015). However, price might overcome

environmental concerns. Price sensitivity (how much importance they placed on price

when choosing a product) negatively moderated the relationship between perceived

harm. This indicated that for those who are highly price sensitive (place greater

importance on price), perceived harm was no longer related to product choice. This was

true even for those with higher levels of environmental concern (Y. Bernard et al., 2015).

Personal relevance of the environmental impacts may be important. (Borin, Cerf, &

Krishnan, 2011) looked at participants’ intentions towards not only bar soap, but also

apples, paper and MP3 players. They found indications (descriptive statistics only) that the

intention to purchase products that had the least direct implications for the users health,

namely the MP3 players and the paper, were less affected by the environmental

information compared to the products with more direct health implications (bar soap and

apples).

Which informational characteristics are most/least effective: The studies which explored

intention to purchase laundry detergent further suggested that on-package,

environmental information had an effect on purchase intentions, regardless of whether

that message was perceived as weak (i.e. vague) or strong (i.e. specific; Spack et al., 2012).

However, combining environmental information or logo with other packaging attributes

to signal pro-environmental credentials may be important, such as the colour (Pancer et

al., 2017), being visibly made from less harmful materials (Magnier & Schoormans, 2015)

or by being certified by an independent, third party (Brach et al., 2018). This is due to the

potential for products with environmental labels being perceived as less effective or a

financial loss risk (Brach et al., 2018; Pancer et al., 2017).

A contradiction between a company’s green advert and their environmental performance

was found to interact. As outlined in the primary research question section, a green

advertisement did not have a significant effect on purchase intentions for insecticide

(Nyilasy et al., 2014). However, there was a significant interaction with the company’s

environmental performance (manipulated to be high, low or none). This interaction

suggested that the negative effect of a low environmental performance on purchase

intentions was strengthened by the presence of the green advertisement. Therefore, a

contradiction between a company’s advertisement and practice may reduce purchase

intentions for insecticide.

The presence of other labelled products may influence selection of a green-labelled

product. Hahnel et al. (2015) found that the number of products available in an online

store, influenced how much money participants spent on green products. When the ratio

of products with officially certified green labels to products without green labels was

higher, the average money spent by participants on green products was significantly

higher than if the ratio was reversed. For each ratio, the total spend was not significantly

different, therefore, although spending the same total, the allocation of that spend

differed. Although this is not as clear-cut as a labelled product versus a non-labelled

product, it does suggest that that a shopping context in which there is a greater presence

of products labelled with an environmental information, consumers may have a tendency



to spend more on environmentally sustainable products. The participants’ ecological

motivations positively correlated with the amount of money spent on green-labelled

products.

3.2.4 Automotive

Primary research question; automotive

Automotive confidence statements:

◼ There is contested evidence for the influence of environmental impact information

influencing vehicle choice.

In terms of self-reported past use of environmental sustainability information when

purchasing a car, a relatively low number of consumers report using them. For instance,

72% of 120 respondents felt that the Energimakering label in Norway had not influenced

their decision to purchase their car (Foudi et al., 2018). Similarly, only 14% of 2,01928 said

they would use an environmental claim in their purchasing decision for a car (Fletcher,

Fell, Wilkins, & Townend, 2011). However, two studies used choice experiments. Both

found significant effects of their environmentally sustainable information on participant

vehicle choice. Participants29 were more likely to choose a vehicle with a better “Global

warming pollution score” (Koo, Kim, Hong, Choi, & Lee, 2012). Likewise, after price,

participants30 were most influenced by the vehicle’s “energy efficiency grade” with an

increase in the efficiency grade associated with a $4689 (£3,665.93) increase in the mean

WTP (Noblet, Teisl, & Rubin, 2006).

Note, no evidence on secondary research questions was extracted for Automotives.

3.2.5 Buildings and construction

Primary research question; buildings and construction

Buildings and construction confidence statements:

◼ There is evidence that environmental impact information can influence choice of

purchase of residential building (confidence = medium).

◼ There is evidence that energy performance information is related to greater WTP for

a rented flat (confidence = low).

Self-reported use of energy performance labels suggest that the labels are only used by a

minority of homebuyers. In a survey of homebuyers in EU and associated countries, only

50% (n= 3,155) saw the Energy Performance Certificate (EPC) before they made an offer

and only 33% of this group then considered the EPC to be an important factor (Tigchelaar,

28 in the UK

29 in Korea

30 in the USA



Backhaus, & de Best-Waldhober, 2011). Similarly, 30% of Irish respondents (n= 501) and

7% of Slovenian respondents (n= 426) indicated that the building energy rating (BER)

certification had influenced their property purchasing decisions (Foudi et al., 2018).

In contrast to the self-reported use, surveys indicate that energy performance labels can

influence choice and WTP. For instance, in an experimental survey31, the presence of an

energy efficiency certificate on a mock flat advertisement, compared to no certificate,

increased participants’ willingness to rent one of the flats. However increasing the grade

of the energy efficiency did not have a significant effect and so, the presence of the

certificate, regardless of its grade, is the most important influence (Jang, Kim, & Kim, 2018).

A survey study32, however, did find WTP for a house with a BREEAM label, a wider

sustainability label for buildings, decreased form 44.2% for the Platinum (highest level) to

11.7% for Bronze (the lowest level) with the indicated mean WTP (for those who would)

also dropping from 4% of the price to 1.3% (Yau, 2012).

Secondary research question; buildings and construction

Which audience factors are relevant: As with other products’ labels, understanding of the

building labels may be important for their effectiveness. Compared to those not living in

a green property, those who already lived in a green property indicated a higher WTP for

a prospective green property. However, once additional information was provided about

the environmental performance of the green property (i.e. what the “green” label

signified), WTP of those not living in a green home significantly increased (although it

remained lower than those already in a green property). Again, this suggests that

understanding of what a label signifies is related to what people are willing to pay for that

label (Zhanget al, 2016).

3.2.6 Paper and Wood Products

Primary research question; paper and wood products

Paper and Wood Products confidence statements:

◼ There is evidence that forest certification positively relates to WTP and preference for

wooden tables (confidence = medium).

◼ There is evidence that labels indicating reduced environmental impacts have a

positive influence on intentions to purchase paper products (confidence = medium).

One study33 explored an existing label, the Nordic Swan. Based on self-reported past

purchases of toilet paper, paper towels and detergents, (Bjørner, Hansen, & Russell, 2004)

found that the marginal willingness to pay for the Nordic Swan label varied by product.

31 in Korea

32 in Korea

33 in Denmark



Toilet paper was their most robust findings with a marginal willingness to pay of between

13% and 18% of the price. The WTP was not significant for paper towels34.

Three studies explored the effect of environmental information specifically on paper

products (Y. Bernard et al., 2015; Borin et al., 2011). These two studies investigated

negative labels, as well as positive ones i.e. labels which indicated the product had either

a positive or a negative environmental impact. Y. Bernard et al. (2015) did not have a

control condition, but found that purchase intentions were significantly higher towards

paper towels with a green traffic-light symbol on the packaging (explained to participants

as meaning environmentally friendly) than paper towels with a red traffic-light symbol on

them (explained to the participant as being environmentally harmful). Similarly, Borin et

al. (2011) found that purchase intentions increased with positive environmental messages

(the absence of harmful processes and impacts) and decreased with negative

environmental messages (the presence of harmful processes and impacts). These

increases and decreases were relative to no environmental message. The negative

environmental message had a slightly greater impact on intentions than the positive

message did. The final study used sales data from an online store to determine a WTP

premium of 69.9% for paper towels with an ecolabel indicating recycled, post-consumer

content (average price of paper towels sold was $2.25; Srinivasan, 2009).

Wooden furniture was explored in relation to forest certificates indicating sustainably

sourced wood. A couple of studies explored WTP for a table with a certified sustainable

forest label versus an unlabelled table. There was variation in the findings depending on

the English and Norwegian participants, the method used to estimate the models and the

consumer characteristics. As such, WTP in the British sample varies between 1.6%

(Veisten, 2002) and 16% (Veisten, 2007) and between 1% and 7.5% in the Norwegian

sample. Using two existing forestry labels, Swiss Quality label and Forest Stewardship

Council, Hansmann, Koellner, and Scholz (2006) found that, on average, participants were

willing to pay a price premium of 5% for a labelled wooden table. However, the number

of participants who were willing to pay a price premium was significantly lower when only

the logo was present on the product compared to when there was also an explanation of

what logo signifies. Again, this highlights the role of knowledge. Finally, compared to a

wooden table presented with no environmental certification, in a UK and US sample, both

an environmental non-government organisation (NGO) and a forest government

organisation label were associated with greater preference (Aguilar & Cai, 2010). Overall,

the evidence for certified wood suggests that certification of wooden products can

influence WTP and product preference.

WTP for certified wood products may vary with the product, however. In a survey35,

Archer, Kozak, and Balsillie (2005) found that the majority of participants indicated an

intention to purchase wood products that had been certified, with

newspapers/magazines only for 55%, but tissues/towels (68%), furniture (68%), and

building products (72%) being higher. This was only a survey and the products surveyed

were not given any other attributes.

34 The authors speculated that this is because green consumers in Denmark choose to avoid using paper towels and instead rely

more on a dishcloth to wipe up spills etc.

35 in Canada



Secondary research questions; paper and wood products

Which other product characteristics shape decisions: Price had a negative relationship on

wooden table choice (our of a certified or non-certified table), suggesting participants

would prefer the lower priced table (less likely to select the higher priced table) (Aguilar &

Cai, 2010). The influence of price, however, may be due to the weight people give to price

compared to environmental concerns in their product decision making. For instance,

those who felt that a product’s environmental attributes were more important than its

price and/or quality more frequently selected the 10% more expensive, green labelled

office products (calendars, office chair, shelf, binders, paper, plates, pens and cleaner)

compared to those who felt that price and/or quality were relatively more important (Ngo,

2008). Likewise, participants who felt that the social and ecological aspects of forests are

more important than the economic aspects had a stronger intention pay attention to

wood labels and would be willing to pay an increased price for labelled products

(Hansmann et al., 2006).

Which audience factors are relevant: Pre-existing objective knowledge of labels did correlate

with WTP for a labelled wooden table but not in a way that was statistically significant

(Hansmann et al., 2006). In a separate study, placing greater importance on brand was

found to not significantly correlate with past purchases of ecological paper (Testa et al.,

2015).

Gender differences were seen with both wooden tables and ecological paper. For wood

products, women were 35.1% less likely to buy wood products certified by NGO versus no

certification agency compared males in the sample (Aguilar & Cai, 2010). In contrast,

women were more likely to self-report having purchased ecological paper products than

men (Testa et al., 2015). Age and education had no relationship with past purchasing

behaviour for ecological paper (Testa et al., 2015). Srinivasan (2009) also found no

significant effect of education on the probability of purchasing ecolabelled paper towels,

but there was a statistically significant negative relationship with age and income, such

that greater age and greater income were associated with a decreased probability of

purchasing ecolabelled paper towels.

3.2.7 Textiles and clothing

Primary research question; textiles and clothing

Textile confidence statements:

◼ There is evidence that, compared to no label, sustainable, all natural, eco-friendly,

and organic labels have a positive influence on WTP for woollen socks (confidence =

medium).

◼ There is evidence that recycled and reclaimed material labels positively related to

clothing purchase intentions (confidence = medium).

◼ There is contested evidence that recycled material labels influence clothing choice.



◼ There is evidence that information on the environmental benefits of sustainable

clothing does not influence intentions to purchase “sustainable clothes” 36 (confidence

= low).

◼ There is evidence that a lifespan label positively influences choice of clothing


Focusing on conventional, sustainable, all natural, eco-friendly, and organic forms of wool,

J. C. Bernard, Hustvedt, and Carroll (2013) found that the bids in an experimental

auction37, for the conventional wool socks were the lowest out of the five production

types. Comparing bids from before an explanation of the production types was given, to

bids after the explanation was given, a reduction in the WTP for the conventional socks

was observed while a rise in the WTP for organic socks was observed (‘all natural’ and ‘eco-

friendly’ did not significantly differ before or after).

Also focusing on recycled or reclaimed materials, Hyllegard, Ogle, and Yan (2014) showed

that students positively evaluated clothing hangtags with pro-social messages on them

(of which one related to using recycled or reclaimed materials). In turn, they found that a

positive evaluation of the pro-social messages was positively related to an intention to

purchase the clothing. In contrast, educational information about the social and

environmental unsustainability of “fast fashion” and the environmental benefits of

sustainable clothing did not have a significant influence on participants’ intentions to

purchase “sustainable clothes” 38 (Barnhoorn, Fiszman, & Poldner, 2018).

A large scale, European experimental survey found that for both trousers and sport shoes,

those with a label showing a longer lifespan than the competing products were chosen an

average of 15% more (Jahnich et al., 2016).

Price is explored in conjunction with labelling in a couple of studies and so they are

discussed together here. For instance, for online purchases (of clothing), the

environmental impact (of its production and delivery) was the second most influential

attribute on people’s choices39, ahead of shipping costs, speed, time and point of delivery,

and return costs. The most influential was price (Stockigt, 2018). Furthermore, using an

experimental shop40, Grasso, McEnally, Widdows, and Herr (2000) manipulated the price

of the clothing as well as its label. Subsequently, price was found to strongly influence the

purchasing behaviour of the participants. Only if the “made from recycled materials”

labelled article of clothing was cheaper or the same price as an article of clothing with no

label, was the recycled article selected (it must be noted that this study was conducted in

the year 2000 with a student sample and so may not be as representative of current, non-

student consumer behaviour).

36 This is the term used in this study by Barnhoorn et al. (2018)

37 in the USA

38 in the Netherlands

39 in Germany

40 in the USA



Secondary research questions; textiles and clothes

Which audience factors are relevant: The participants’ understanding of a label may have

an important influence on its effectiveness. By having participants bid for the woollen

socks before the labels were explained, (J. C. Bernard et al., 2013) showed that the amount

people were willing to pay for the organic and sustainable labelled socks increased after

the implications of the label were explained. Conversely, the willingness to pay for the

conventional socks decreased. The eco-friendly and all natural labels did not significantly

change. The authors suggest that having official definitions and standards for the labels

and ensuring consumer understanding of the meaning of the terms could have an

influence on WTP.

Which informational characteristics are most/least effective: Kim, Lee, and Hur (2012), found

that manipulating the framing of the information relating to the product so that it either

said money will be donated to environmental causes if the product is purchased or it said

that the product was made in a less environmentally harmful (no chemicals) way. There

was no significant relationship between the labels and intention to purchase. However,

the claims interacted with environmental concern such that environmental concern had

a stronger relationship with purchase intentions when the less environmentally harmful

information was shown. A further study suggested that environmental concern also

interacts with the price. Price was a big influence on those who chose conventional

textiles, whereas those who chose eco-labelled textiles were less influenced by price

(Dreyer, Botha, van der Merwe, le Roux, & Ellis, 2016).

3.2.8 Procurement

Primary research question; procurement

Procurement confidence statements:

◼ There is evidence that environmental performance information is used by local

authorities for procurement of services41 (confidence= low).

◼ There is evidence that coach tour operators would be willing to pay more for a coach

company with a green certificate42 (confidence= low).

In terms of organisations as consumers, only two studies which explored the role of

environmental information in procurement were found in this REA; one on Norwegian

local authorities (Michelsen & de Boer, 2009) and one on North American tour operators

(Anderson, Mastrangelo, Chase, Kestenbaum, & Kolodinsky, 2013). For local authorities,

whether the environmental performance information of the private companies,

institutions and non-profit organisations is actively considered during the qualification

and final decisions in procurement. For the qualification phase, 41% said Yes, 41.9% said

No and 17.1% said Do not know (N=105). For the final selection, 50% said Yes, 27.3% said

No and 22.7% said Do not know (N=110). As such, there is some indication that

environmental performance is considered during procurement in Norwegian local

41 A single evidence with a combined score of < 6

42 A single evidence with a combined score of < 6



authorities, but it is not a majority and a sizeable percentage do not know. Similarly, for

the North America tour operators (Anderson et al., 2013), approximately 50% (N = 72) of

respondents indicated that they would be willing to pay more for a coach company that

had a green certificate (a certificate to indicate the coach company was mitigating it's CO2

emissions). Of these, 35% were only willing to pay 1% more.

Secondary research questions; procurement

Which organisational factors are related: A correlation between the size of the municipality

and the use of environmental performance information was found (Michelsen & de Boer,

2009). The reason for this correlation cannot be known, but other factors were also

correlated with size of the municipality, such as the existence of a purchasing department

and a purchasing strategy; both of which are argued to be important for local authorities

to make the most of their purchasing power. As such, they may be important for ensuring

that environmental performance information is used within procurement.

For the tour operators, price and then company reputation were indicated as being the

most important factors when selecting a coach company. No tour operators selected

environmental practices as their most important factor in their choice. Indeed, as the

premium increased, fewer tour operators indicated a willingness to pay it with 35%

indicating that they would be WTP 1% more, 12% indicating WTP 5% more and 4%

indicating WTP an unspecified amount more. The tour operator companies' own

environmental practices may be related to the WTP. In descriptive statistics only, of those

that indicated engaging in 2 or more environmental practices as a company, 26% were

WTP more for the green certified coach. In comparison, of those that indicated engaging

in 0 environmental practices, only 11% were WTP more.

3.3 Summary of synthesis

Overall, studies of appliances were most common in the evidence base, with the energy

consumption and ratings and monetary running costs the most frequent information

tested. There is evidence that the EU Energy Label positively influences the purchase,

choice, or intentions towards, more energy efficient appliances (confidence = high). There

is also some evidence that other energy labels (Energy Frontiers and China Energy

Efficiency) have an effect, although this is based on too small of an evidence base at the

present to be rated as greater than low confidence in the context of the REA. There is

contested evidence for the ENERGY STAR label having an influence on consumers and for

monetary running costs having greater effect than energy consumption. In contrast, there

is evidence that the Australian Energy Rating label does not have an influence on online

shopping behaviour (confidence = medium).

For the environmental sustainability aspects of appliances other than energy, the

evidence base is smaller. However, two large-scale European studies provide evidence

that the addition of carbon footprint information or environmental impact information to

an energy label increases WTP (confidence = medium). Likewise, there is evidence that a

lifespan label increases appliance preference, with higher lifespan being associated with

a greater likelihood of being chosen (confidence = medium).



There were few studies on consumer electronics and ICT (televisions, laptops and

single-use43 cameras) and these provided contested evidence for the effect of energy

consumption on WTP for more efficient televisions and evidence that the Korean Energy

Saving label is associated with a greater WTP for labelled laptops (confidence = medium).

For non-energy aspects, there is evidence that the addition of carbon footprint

information or environmental impact information to an energy label increases willingness

to pay for televisions (confidence = medium). However, there is also evidence that a

lifespan label does not increase preferences for televisions but does increase it for

printers and smart phones (confidence = medium). For single-use cameras, there is

evidence for recycled materials or remanufactured labelling increasing WTP (confidence

= medium).

Some studies investigated cleaning/home chemical products or cosmetic products. There

is evidence that environmental information/labels on intentions to purchase laundry

detergent (confidence = high). However, there is evidence that carbon emission

information and green advertising do not influence the purchase of insecticide

(confidence = medium), but that sustainability information does influence purchases

hairspray and that environmental impact indicators influence the selection of less

impactful washing-up liquid (confidence = medium).

In terms of evidence for automotive and buildings and construction, there is contested

evidence for the environmental impact information influencing vehicle choice, but there

is evidence that environmental impact information is related to greater WTP for renting a

flat (confidence = medium). There is also evidence that information on the energy

performance of a building can influence the choice of residential building (confidence =

medium). For paper and wood products there is also evidence that forest certification

positively relates to WTP and preference for wooden tables and that environmental

impact information has a positive influence on intentions to purchase paper products


For textiles, there is evidence that compared to no label, sustainable, all natural, eco-

friendly, and organic labels have a positive influence on WTP for woollen socks; that

recycled and reclaimed material labels positively related to clothing purchase intentions;

and that a lifespan label positively influences choice of clothing (confidence = medium).

However, there is also evidence that information on the benefits of sustainable clothing

does not influence “intentions to purchase “sustainable clothes” (confidence = low).

Therefore, some forms of environmentally sustainable information influence clothing

choice, but others may not.

Evidence for procurement (i.e. organisations as consumers) was limited in number and

quality in the evidence base. There is evidence that environmental performance

information is used by local authorities for procurement of services and this may be

related to the size of the municipality (confidence = low). There is also evidence that coach

tour operators would be willing to pay more for a coach company with a green certificate,

particularly if the company itself is engaged in green practices (confidence = low).

43 A single-use camera is not electronic but has been put in this product category as a best fit.



4.0 Conclusions and Implications

Here, conclusions and implications of the synthesis are presented and drawn from

across the products.

With respect to the primary research question:

the answer is, that there are a considerable number of studies, of which many show that

providing information on environmental impact can influence consumers’ buying

decisions, at least in an experimental situation.

However:

• The evidence is heterogeneous and often based on consumer intentions44

As described in section 3.1 Evidence Characteristics, a wide range of products have been

explored in combination with a wide range of environmentally sustainable information.

In turn, this information is presented in a range of different forms, content and framing.

In a case such as the EU Energy Label, which has a standardised form and content and a

typical range of product applicability, there are opportunities to draw conclusions from

many comparable studies and be confident in the positive influence the label can have on

sales of energy efficient appliances. In other cases, such as laundry detergent, there have

also been a relatively large number of studies but the variation in the information used

across each of the studies makes comparisons difficult. Therefore, whilst it can be seen

that environmental sustainability information does positively influence the sales of less

harmful laundry detergent, distinguishing the forms and content of information that are

more or less effective is difficult.

This heterogeneity in terms of information content and form is greatest in the non-energy

information literature. Perhaps this is because some products have a focal sustainability

aspect (e.g. wooden tables and forest certification), whilst others do not (e.g. textiles, with

recycled or organic or sustainable materials) meaning that information content could be

product-determined in some cases and researcher-determined in others. Across the

products, non-energy aspects of environmental sustainability, such as use of recycled

materials, remanufacturing, lifespan, carbon footprint, or environmental impacts do each

have high quality studies investigating them, but the number is currently too low to be

able to have great confidence in the effect and further studies will be needed to test the

initial indications.

The range of outcome measures within the evidence base also adds complexity to the

comparison of studies. Within the evidence assessment criteria for this REA, it was

determined that outcomes of actual purchases would have the most relevance to the

primary research question. However, very few studies in the evidence base used actual

purchases and those that did predominantly investigated energy labels. The purchases in

an experimental setting provided strong evidence, but were again limited in number.

Indeed, within the evidence base the outcomes used were predominantly WTP, choice,

44 rather than actual purchases



and intention. Whilst these outcomes can give an indication of an individual’s potential to

respond to information, as well as other useful insights into the importance of other

interacting factors, they are still a step away from actually making a purchase. This is

additionally important as laboratory/online experiments may show either stronger effects

than field trials or conflicting effects (as is the case with the EU Energy Label and running

costs).

The findings of this REA would suggest that the evidence for individuals as consumers is

more prolific than the evidence available for organisations as consumers. As

organisations can frequently have strong buying power, understanding the use of

environmental information within their procurement strategies will be important if

organisations are to be persuaded to buy and use products which are less

environmentally harmful. What evidence there is in this REA suggests that some

organisations incorporate environmental performance of companies when procuring a

service, but this may be related to the nature of the organisation itself (e.g. appropriate

departments and green practices).

Implications: Giving an answer to the primary research question that adequately captures

the individual nature of information and product combination is challenging. Even

answering it per product would require some qualitative averaging of evidence. In this

REA, a balance between finding opportunities to synthesise, whilst preserving and

representing the diversity in the literature has been sought. Further research is required

using standardised, robust methodologies that enable comparison across products and

information types. In particular, further field trials or experiments that involve the

participant making a purchase (e.g. experimental auctions) are required to have greater

confidence in the evidence for labels, particularly the non-energy ones.

• The relative importance of environmentally sustainable criteria needs greater exploration

As noted when discussing the heterogeneity of the evidence base, the range of

environmentally sustainable information is quite large. As the manufacture of many

products can have multiple, diverse environmental impacts, knowing which aspect will be

most effective at encouraging more sustainable purchases is challenging. There were

some higher quality studies which compared the effect of different environmental

sustainability aspects. Michaud and Llerena (2011) investigated remanufactured, recycled,

and conventional labels on single-use cameras and compared the amounts bid on each

camera in an experimental auction. It was found that recycled and conventional had the

joint highest bids, with remanufactured having the lowest. The authors argue that this

may be due to the remanufactured label being associated with not being new and

therefore, perhaps inferior. Indeed, once the environmental benefits of recycled or

remanufactured were explained, the bids for the remanufactured label increased and the

conventional decreased to the lowest. Recycled remained highest. The conventional label

was also found to receive the lowest bids in an experimental auction for woollen socks (J.

C. Bernard et al., 2013). In this study, the organic label received the highest bids, whilst

sustainable, “all natural” and “eco-friendly” received equal second highest (after terms

were explained). Both studies suggest that, when the environmental impacts of a

conventional product are highlighted and less environmentally harmful options are

available, the desire to pay for the conventional product decreases. The reasons why



“recycled” and “organic” were rated highest in their respective studies can only be

hypothesised, but understanding of the labels may be important (discussed further

below).

One other study45 (Langley et al., 2012) compared the effectiveness of different

environmental sustainability information. Across both choice experiments and

experimental auctions, it was found that WTP for washing machines with an EU Energy

Label that had additional carbon footprint information was higher than for washing

machines with an EU Energy Label that had other additional environmental impacts

information. Both had higher WTP than just the EU Energy Label. Interestingly, the

environmental impacts information contained the same carbon footprint information, but

it had additional water footprint, resource depletion and water eco-toxicity information.

This may suggest that adding one further piece of environmental information is more

effective than multiple, perhaps because it is simpler or quicker to interpret.

Implications: There appear to be preferences amongst consumers for certain aspects of

sustainability (e.g., recycled, organic) over others (e.g., remanufactured), though this may

change as knowledge increases. There are also indications that providing too much

sustainability information may backfire. However, there remains a need for further

research to explore the relative importance of different (and combined) sustainability

criteria in consumer decision-making.

• The influence of environmental information may be product dependent

Some studies within the evidence base looked at the same information, but across

different products. From these studies, it is clear that information or labels that work on

one product, may not work on a different product. For instance, while a lifespan label

influenced choice of washing machines and coffee makers, it did not influence choice of

televisions (Jahnich et al., 2016). The addition of running costs to the EU Energy Label was

not more effective than just the EU Energy Label for vacuum cleaners, fridge freezers, or

washing machines, but it was more effective for tumble-dryers (Kallbekken et al., 2013)

and washer-dryers (DECC, 2014). This was speculated to be due to the higher running

costs and therefore the costs would be higher and more salient than on the other

appliances. Relatedly, Shen and Saijo (2009) speculated that the higher WTP for

refrigerators with an energy label than air conditioners with the same energy label may

have been because refrigerators are used continuously, whereas air-conditioners might

only be used seasonally, and so there is greater opportunity to benefit from energy

efficiency. Other instances, such as the Nordic Swan influencing toilet paper purchases,

but not paper towel purchases46 (Bjørner et al., 2004) or carbon footprint information

increasing WTP for appliances, but not lightbulbs47 (Langley et al., 2012) suggest the

difficulty of applying one label to multiple products.

45 In the evidence base

46 The authors speculated that this is because green consumers in Denmark choose to avoid using paper towels and instead rely

more on a dishcloth to wipe up spills etc.

47 The authors speculated that this was because the lightbulbs cost a lot less than the appliances.



One broad factor that could influence the effectiveness of a label on a product is the

possible implications the product has for the individual’s health. Borin et al. (2011), looked

at participants’ intentions towards bar soap, apples and MP3 players. They found

indications (descriptive statistics only) that the intention to purchase products that had

the least direct implications for the users’ health, namely the MP3 players and the paper,

were less affected by the environmental information compared to the products with more

direct health implications - bar soap and apples. A second factor is how much importance

the individual places on brand when choosing a product. Participants placing greater

importance on brand did not significantly correlate with past purchases of ecological

paper, but it did negatively correlate with past purchases of ecological cleaning products

(Testa et al., 2015).

Implications: Understanding what aspects of the information can be more universally

applied compared to product specific information will be important. There is some

evidence that while energy consumption labels are effective on appliances, the addition

of running costs is only effective on appliances with relatively higher running costs. There

is also evidence that energy labels are less effective on products that are used less

regularly; and that the implications the product has for the consumer’s health and the

importance of brand to the consumer may each interact to shape a label’s influence.

However, more studies which systematically manipulate these factors are needed.

In terms of the secondary questions the main conclusions are:

• Understanding of labels is important for their effectiveness

As shown across a number of studies in the evidence base, knowledge and understanding

of labels and familiarity with them have been found to moderate the effectiveness of

labels/information. In particular the studies which had pre- and post-explanation

outcomes are most indicative of the importance of understanding as in both, the WTP for

the labels (including recycled, remanufactured, organic) increased once the mitigation of

environmental impacts that the label signified was explained. At the same time, a greater

understanding of the environmental impacts that the non-labelled products had,

decreased participants’ WTP for them (J. C. Bernard et al., 2013; Michaud & Llerena, 2011).

Whilst the WTP for organic socks (already the highest) further increased post-explanation,

WTP for a recycled camera (joint highest with conventional) did not increase further.

Therefore, for the single-use cameras, the relative amount people would pay for the

recycled camera did increase, but only because the WTP for the conventional decreased.

Implications: An increase in knowledge of the environmental impacts associated with

products’ manufacturing and the mitigation of these impacts that the labels signify could

have an important bearing on the consumer’s choices and the relative amounts they are

WTP. As such, there is a need for broader consumer education about the environmental

sustainability implications of both labelled and unlabelled products to ensure that labels

work most effectively. Further research into the influence of the availability of labelled

products on the WTP for unlabelled products is also warranted.



• The role of information interacts with price sensitivity and varies across different

consumer groups

Across products, price was often reported as being the most influential factor in product

choice. Price was also found to interact with the influence of the environmental

information. For instance, in the stated WTP studies, the proportion of those who were

WTP a premium for a labelled product decreased as the premium increased. Likewise the

frequency of the labelled product being chosen decreased as the price increased. Price

was also found to negatively interact with the perceived environmental harm of the

product. As such, compared to those who were less concerned about price, those who

were more concerned about price, were not influenced by their perception of the labelled

washing-up liquid’s environmental harm. This was true even for those who had higher

levels of environmental concern. Similarly, those who placed greater importance on the

price or quality of a wooden table than they did on its environmental attributes, less

frequently selected the higher price premium.

There was some evidence that the influence of energy and lifespan labels decreases with

age of the consumer; however, there was no relationship with age and ecological cleaning

product or ecological toilet paper purchasing. Gender differences may exist for different

labels; for instance, preference for refrigerators with the ENERGY STAR label was higher

among men than women. Further, women were 35.1% less likely to buy wood products

certified by an NGO versus no certification agency compared men in the sample. However,

in a separate study women were more likely than males to base their choice of appliances

on the lifespan label (Jahnich et al., 2016).

Implications: The evidence would suggest there is a limit to the premium people are WTP

for labelled products. Furthermore, if someone places a lot of importance on price, they

are unlikely to be influenced by environmental sustainability information, even if they

have high levels of environmental concern. Evidence is mixed about how demographic

differences like age and gender influence the effectiveness of environmental information,

highlighting a need for further research to understand and segment different consumer

groups.

4.1 Overall conclusions and recommendations for future research

Overall, regarding the primary research question, the evidence in this REA suggests that

energy consumption information can influence purchase behaviour and intentions for

appliances (particularly om the case of the EU Energy Label). However, the effect of

information on using monetary running costs instead of (or in addition to) energy

consumption is unclear: the evidence is contested. For other environmentally sustainable

aspects, the findings are less certain; however there are emerging findings that labelled

products may be preferred over unlabelled products. Which form of sustainability is most

influential may depend on the consumer’s understanding of what the label signifies.

Price is likely to be a strongly influencing factor in many purchase choices; while there is

some evidence for environmental concern positively influencing product choice, price

concerns may override environmental concern. On the other hand, the WTP literature

suggests that, to a point, consumers may be WTP a premium for labelled products. In all



cases, the influence the information has is likely to depend on the product, with the same

information potentially having an influence on one product but not another.

Further research will be needed to systematically manipulate information across a range

of products and consumer groups to ascertain which aspect of environmental

sustainability will be most effective for which product and for which consumer group. It

will also be important to consider how the effectiveness of this information on purchase

decisions might be strengthened or mitigated by other product characteristics, such as

price or brand, or by complementary interventions (e.g., sustainability education

programs). As field trials are difficult to instigate, forms of experimental design are

required that allow participants to purchase products, whilst still allowing manipulation

of product labels. Studies using online stores, for example, could offer opportunities to

conduct field trials in a more controlled environment. Findings from these can then help

inform field trials in physical retail environments. However, qualitative research

(interviews or focus groups) may be necessary to help understand why one form of

environmentally sustainable information is appealing on one product, but then not on

another. Testing aspects of environmental sustainability that are clear in their focus, such

as “recycled parts” (as opposed to vaguer claims, such as “eco-friendly”) during future

studies will help with comparability of effects between different studies (even if a

complete standardisation is not possible) and help to give a clearer understanding of what

sustainability aspect participants are responding to.

5.0 References

Aguilar, F. X., & Cai, Z. (2010). Conjoint effect of environmental labeling, disclosure of

forest of origin and price on consumer preferences for wood products in the US

and UK. Ecological Economics, 70(2), 308-316. doi:10.1016/j.ecolecon.2010.09.002

Allcott, H., & Sweeney, R. L. (2017). The Role of Sales Agents in Information Disclosure:

Evidence from a Field Experiment. Management Science, 63(1), 21-39.

doi:10.1287/mnsc.2015.2327

Anderson, L., Mastrangelo, C., Chase, L., Kestenbaum, D., & Kolodinsky, J. (2013). Eco-

labeling motorcoach operators in the North American travel tour industry:

analyzing the role of tour operators. Journal of Sustainable Tourism, 21(5), 750-764.

doi:10.1080/09669582.2012.709859

Andor, M., Gerster, A., & Sommer, S. (2016). Consumer inattention, heuristic thinking and

the role of energy labels.

Archer, H., Kozak, R., & Balsillie, D. (2005). The impact of forest certification labelling and

advertising: An exploratory assessment of consumer purchase intent in Canada.

Forestry Chronicle, 81(2), 229-244. doi:10.5558/tfc81229-2

ArtcraftResearch. (2005). Appliance Performance Labelling in Australia and New Zealand.

Barnhoorn, A., Fiszman, B. P., & Poldner, K. (2018). SUSTAINABLE FASHION.

Barthel, C., Kaselofsky, J., & Madry, T. (2015). Evaluating soft measures: potential impacts

of a web-based information tool about energy efficient products.

Bernard, J. C., Hustvedt, G., & Carroll, K. A. (2013). What is a label worth? Defining the

alternatives to organic for US wool producers. Journal of Fashion Marketing and

Management: An International Journal, 17(3), 266-279. doi:10.1108/JFMM-01-2013-

0009



Bernard, Y., Bertrandias, L., & Elgaaied-Gambier, L. (2015). Shoppers’ grocery choices in

the presence of generalized eco-labelling. International Journal of Retail and

Distribution Management, 43(4-5), 448-468. doi:10.1108/IJRDM-12-2013-0218

BETA. (2018). Energy labels that make cents: testing energy rating labels on appliances

sold online. In. Commonwealth of Australia: Department of the Prime Minister

and Cabinet.

Bjørner, T. B., Hansen, L. G., & Russell, C. S. (2004). Environmental labeling and

consumers' choice - An empirical analysis of the effect of the Nordic Swan. Journal

of Environmental Economics and Management, 47(3), 411-434.

doi:10.1016/j.jeem.2003.06.002

Blasch, J., Filippini, M., & Kumar, N. (2017). Boundedly rational consumers, energy and

investment literacy, and the display of information on household appliances.

Resource and Energy Economics. doi:10.1016/j.reseneeco.2017.06.001

Borin, N., Cerf, D. C., & Krishnan, R. (2011). Consumer effects of environmental impact in

product labeling. Journal of Consumer Marketing, 28(1), 76-86.

doi:10.1108/07363761111101976

Brach, S., Walsh, G., & Shaw, D. (2018). Sustainable consumption and third-party

certification labels: Consumers' perceptions and reactions. European Management

Journal, 36(2), 254-265. doi:10.1016/j.emj.2017.03.005

Cho, Y. N. (2015). Different Shades of Green Consciousness: The Interplay of

Sustainability Labeling and Environmental Impact on Product Evaluations. Journal

of Business Ethics, 128(1), 73-82. doi:10.1007/s10551-014-2080-4

Clayton, S., Devine-Wright, P., Stern, P. C., Whitmarsh, L., Carrico, A., Steg, L., . . . Bonnes,

M. (2015). Psychological research and global climate change. Nature Climate

Change, 5(7), 640.

Consumer Focus. (2012). Under the influence? Consumer attitudes to buying appliances

and energy labels.

Corner, A., Pidgeon, N., & Parkhill, K. (2012). Perceptions of geoengineering: public

attitudes, stakeholder perspectives, and the challenge of ‘upstream’engagement.

Wiley Interdisciplinary Reviews: Climate Change, 3(5), 451-466.

Davis, L. W., & Metcalf, G. E. (2016). Does Better Information Lead to Better Choices?

Evidence from Energy-Efficiency Labels. Journal of the Association of Environmental

and Resource Economists, 3(3), 589-625. doi:10.1086/686252

DECC. (2014). Evaluation of the DECC/John Lewis energy labelling trial. London

Dreyer, H., Botha, E., van der Merwe, D., le Roux, N., & Ellis, S. (2016). CONSUMERS'

UNDERSTANDING AND USE OF TEXTILE ECO-LABELS DURING PRE-PURCHASE

DECISION MAKING. Journal of Family Ecology and Consumer Sciences, 1-19.

Egan, C., Payne, C. T., & Thorne, J. (2000). Interim findings of an evaluation of the U.S.

energy guide label. Proceedings ACEEE Summer Study on Energy Efficiency in

Buildings, 8, 8.77-78.91.

Feldman, S., & Tannenbaum, B. (2000). Swoosh!? Awareness and Effects of the ENERGY

STAR Brand in Wisconsin Appliance Efficiency Programs. ACEEE Summer Study

2000, 6.107-119.

Fletcher, J., Fell, D., Wilkins, C., & Townend, R. (2011). Consumer understanding of green

terms: A report to the Department for Environment, Food and Rural Affairs. In.

London: Department for Environment, Food and Rural Affairs.



Foudi, S., de Ayala, A., López, E., & Galarraga, I. (2018). Consumer survey based empirical

evidence on consumer’s energy efficiency choices across different consumer

groups and geographical locations: survey results.

GFK. (2014). Consumer Market Study on Environmental Claims for Non-food products.

Retrieved from Luxembourg: Publications Office of the European Union, 2014:

Goucher-Lambert, K., & Cagan, J. (2015). The Impact of Sustainability on Consumer

Preference Judgments of Product Attributes. Journal of Mechanical Design,

Transactions of the ASME, 137(8). doi:10.1115/1.4030271

Grasso, M. M., McEnally, M., Widdows, R., & Herr, D. G. (2000). Consumer behavior

toward recycled textile products. Journal of the Textile Institute, 91(2), 94-106.

doi:10.1080/00405000008659530

Gu, H., Morrison, P., & Yu, C. (2009). Energy Labels: Formats and Impact on Consumption

Behaviour.

Hahnel, U. J. J., Arnold, O., Waschto, M., Korcaj, L., Hillmann, K., Roser, D., & Spada, H.

(2015). The power of putting a label on it: Green labels weigh heavier than

contradicting product information for consumers' purchase decisions and post-

purchase behavior. Frontiers in Psychology, 6. doi:10.3389/fpsyg.2015.01392

Hansmann, R., Koellner, T., & Scholz, R. W. (2006). Influence of consumers'

socioecological and economic orientations on preferences for wood products

with sustainability labels. Forest Policy and Economics, 8(3), 239-250.

doi:10.1016/j.forpol.2004.06.005

Heinzle, S. L. (2012). Disclosure of Energy Operating Cost Information: A Silver Bullet for

Overcoming the Energy-Efficiency Gap? Journal of Consumer Policy, 35(1), 43-64.

doi:10.1007/s10603-012-9189-6

Heinzle, S. L., & Wüstenhagen, R. (2012). Dynamic adjustment of eco-labeling schemes

and consumer choice - the revision of the EU energy label as a missed

opportunity? Business Strategy and the Environment, 21(1), 60-70.

doi:10.1002/bse.722

Houde, S. (2018). How consumers respond to product certification and the value of

energy information. Rand Journal of Economics, 49(2), 453-477. doi:10.1111/1756-

2171.12231

Hyllegard, K. H., Ogle, J. P., & Yan, R. N. (2014). College students’ responses to prosocial

marketing claims on apparel hang tags. Journal of Fashion Marketing and

Management, 18(3), 269-283. doi:10.1108/JFMM-12-2012-0075

Jahnich, M., Boulbry, G., & Dupre, M. (2016). The influence of lifespan labelling on

consumers. European Economic and Social Committee. In. Brussels.

Jain, M., Rao, A. B., & Patwardhan, A. (2018). Consumer preference for labels in the

purchase decisions of air conditioners in India. Energy for Sustainable

Development, 42, 24-31. doi:10.1016/j.esd.2017.09.008

Jang, D. C., Kim, B., & Kim, S. H. (2018). The effect of green building certification on

potential tenants' willingness to rent space in a building. Journal of Cleaner

Production, 194, 645-655. doi:10.1016/j.jclepro.2018.05.091

Jeong, G., & Kim, Y. (2015). The effects of energy efficiency and environmental labels on

appliance choice in South Korea. Energy Efficiency, 8(3), 559-576.

doi:10.1007/s12053-014-9307-1

Kallbekken, S., Sælen, H., & Hermansen, E. A. T. (2013). Bridging the Energy Efficiency

Gap: A Field Experiment on Lifetime Energy Costs and Household Appliances.

Journal of Consumer Policy, 36(1), 1-16. doi:10.1007/s10603-012-9211-z



Kim, H., Lee, E. J., & Hur, W. M. (2012). The Normative Social Influence on Eco-Friendly

Consumer Behavior: The Moderating Effect of Environmental Marketing Claims.

Clothing and Textiles Research Journal, 30(1), 4-18. doi:10.1177/0887302X12440875

Koo, Y., Kim, C. S., Hong, J., Choi, I. J., & Lee, J. (2012). Consumer preferences for

automobile energy-efficiency grades. Energy Economics, 34(2), 446-451.

doi:10.1016/j.eneco.2011.12.012

Langley, E., Dickman, A., Jenner, M., Duke, C., Suter, J., Sinn, M., & Dolley, P. (2012).

Research on EU product label options. European Commission, London.

London Economics. (2014). Study on the impact of the energy label‐and potential

changes to it‐on consumer understanding and on purchase decisions. London

Economics and Ipsos for the European Commission, Brussels.

Lupiáñez-Villanueva, F., Tornese, P., Giuseppe, V. A., & Gaskell, G. (2018). Assessment of

different communication vehicles for providing Environmental Footprint

information.

Magnier, L., & Schoormans, J. (2015). Consumer reactions to sustainable packaging: The

interplay of visual appearance, verbal claim and environmental concern. Journal

of Environmental Psychology, 44, 53-62. doi:10.1016/j.jenvp.2015.09.005

Michaud, C., & Llerena, D. (2011). Green consumer behaviour: An experimental analysis

of willingness to pay for remanufactured products. Business Strategy and the

Environment, 20(6), 408-420. doi:10.1002/bse.703

Michelsen, O., & de Boer, L. (2009). Green procurement in Norway; a survey of practices

at the municipal and county level. Journal of Environmental Management, 91(1),

160-167. doi:10.1016/j.jenvman.2009.08.001

Newell, R. G., & Siikamäki, J. (2014). Nudging energy efficiency behavior: The role of

information labels. Journal of the Association of Environmental and Resource

Economists, 1(4), 555-598.

Ngo, K. (2008). The influence of environmental claims on consumers’ willingness to

purchase. In.

Nguyen, T. N., Pham, T. H., Nhan Nguyen, T. T., Chu, M. D., & Pham, T. H. (2018).

Promoting Energy Efficiency in an Emerging Market: Insights and Intervention

Strategies. Strategic Planning for Energy and the Environment, 38(2), 70-80.

doi:10.1080/10485236.2018.12027909

Niederberger, A., & Champniss, G. (2017). Flip sides of the same coin? A simple efficiency

score versus energy bill savings information to drive consumers to choose more

energy-efficient products. Energy Efficiency, 1-15. doi:10.1007/s12053-017-9542-3

Noblet, C. L., Teisl, M. F., & Rubin, J. (2006). Factors affecting consumer assessment of

eco-labeled vehicles. Transportation Research Part D-Transport and Environment,

11(6), 422-431. doi:10.1016/j.trd.2006.08.002

Nyilasy, G., Gangadharbatla, H., & Paladino, A. (2014). Perceived Greenwashing: The

Interactive Effects of Green Advertising and Corporate Environmental

Performance on Consumer Reactions. Journal of Business Ethics, 125(4), 693-707.

doi:10.1007/s10551-013-1944-3

Palomo, R. R., Martínez, C. V., & Bosch, I. C. (2015). The influence of social and

environmental labels on purchasing: An information and systematic-heuristic

processing approach. Innovar, 25(57), 121-131.

doi:10.15446/innovar.v25n57.50356



Pancer, E., McShane, L., & Noseworthy, T. J. (2017). Isolated Environmental Cues and

Product Efficacy Penalties: The Color Green and Eco-labels. Journal of Business

Ethics, 143(1), 159-177. doi:10.1007/s10551-015-2764-4

Sammer, K., & Wüstenhagen, R. (2006). The influence of eco-labelling on consumer

behaviour - Results of a discrete choice analysis for washing machines. Business

Strategy and the Environment, 15(3), 185-199. doi:10.1002/bse.522

Shen, J., & Saijo, T. (2009). Does an energy efficiency label alter consumers' purchasing

decisions? A latent class approach based on a stated choice experiment in

Shanghai. Journal of Environmental Management, 90(11), 3561-3573.

doi:10.1016/j.jenvman.2009.06.010

Spack, J. A., Board, V. E., Crighton, L. M., Kostka, P. M., & Ivory, J. D. (2012). It's Easy Being

Green: The Effects of Argument and Imagery on Consumer Responses to Green

Product Packaging. Environmental Communication-a Journal of Nature and Culture,

6(4), 441-458. doi:10.1080/17524032.2012.706231

Srinivasan, A. K. B., G. C. (2009). Ecolabeled paper towels: Consumer valuation and

expenditure analysis. Journal of Environmental Management, 90(1), 314-320.

doi:10.1016/j.jenvman.2007.09.007

Stadelmann, M., & Schubert, R. (2018). How Do Different Designs of Energy Labels

Influence Purchases of Household Appliances? A Field Study in Switzerland.

Ecological Economics, 144, 112-123. doi:10.1016/j.ecolecon.2017.07.031

Stockigt, G. S., J.; Brand, M. (2018). Providing sustainability information in shopping

situations contributes to sustainable decision making: An empirical study with

choice-based conjoint analyses. Journal of Retailing and Consumer Services, 43, 188-

199. doi:10.1016/j.jretconser.2018.03.018

Stokes, A. & Turri, A.M.. (2015). Consumer perceptions of carbon labeling in print

advertising: Hype or effective communication strategy? Journal of Marketing

Communications, 21(4), 300-315. doi:10.1080/13527266.2012.762420

Tang, E., Fryxell, G. E., & Chow, C. S. F. (2004). Visual and verbal communication in the

design of eco-label for green consumer products. Journal of International

Consumer Marketing, 16(4), 85-105. doi:10.1300/J046v16n04_05

Testa, F., Iraldo, F., Vaccari, A., & Ferrari, E. (2015). Why eco-labels can be effective

marketing tools: Evidence from a study on italian consumers. Business Strategy

and the Environment, 24(4), 252-265. doi:10.1002/bse.1821

Tigchelaar, C., Backhaus, J., & de Best-Waldhober, M. (2011). Consumer response to

energy labels in buildings, Recommendations to improve the Energy

Performance Certificate and the Energy Performance of Buildings Directive based

on research findings in 10 EU countries. Deliverable, 6, 41.

Veisten, K. (2002). Potential demand for certified wood products in the United Kingdom

and Norway. Forest Science, 48(4), 767-778.

Veisten, K. (2007). Willingness to pay for eco-labelled wood furniture: Choice-based

conjoint analysis versus open-ended contingent valuation. Journal of Forest

Economics, 13(1), 29-48. doi:10.1016/j.jfe.2006.10.002

Verplanken, B., & Wood, W. (2006). Interventions to break and create consumer habits.

Journal of Public Policy & Marketing, 25(1), 90-103.

Waechter, S., Sütterlin, B., & Siegrist, M. (2015). Desired and undesired effects of energy

labels - An eye-tracking study. Plos One, 10(7). doi:10.1371/journal.pone.0134132



Ward, D. O., Clark, C. D., Jensen, K. L., Yen, S. T., & Russell, C. S. (2011). Factors influencing

willingness-to-pay for the ENERGY STAR (R) label. Energy Policy, 39(3), 1450-1458.

doi:10.1016/j.enpol.2010.12.017

Yau, Y. (2012). Eco-labels and willingness-to-pay: A Hong Kong study. Smart and

Sustainable Built Environment, 1(3), 277-290. doi:10.1108/20466091211287146

Zhang, L., Sun, C., Liu, H. Y., & Zheng, S. Q. (2016). The role of public information in

increasing homebuyers' willingness-to-pay for green housing: Evidence from

Beijing. Ecological Economics, 129, 40-49. doi:10.1016/j.ecolecon.2016.05.010

Zhou, H., & Bukenya, J. O. (2016). Information inefficiency and willingness-to-pay for

energy-efficient technology: A stated preference approach for China Energy

Label. Energy Policy, 91, 12-21. doi:10.1016/j.enpol.2015.12.040



Appendix 1 – REA Protocol

Background


are used to persuade buyers (individuals and organisations) to purchase products with

lower, negative environmental impact. In particular, labels are well established,

geographically widespread (used in both the developed and developing world), can cover

a wide range of sustainability considerations, and can be established by a range of

stakeholders (mainly environmental third-sector organisations, Governments and their

agencies). Labels cover a wide range of products (electrical appliances; food; vehicles;

buildings; services; textiles; packaging) and environmental aspects (energy use; carbon

footprint; sustainability; lifecycle impact; water use; reparability and durability). Further, a

recognition of the purchasing power of organisations, particularly national and local

government has resulted in the development of green procurement guides. These aim to

increase the uptake of products with lower environmental impact by providing criteria for

purchasers to use. Additional information sources include web sites which rate a range of

products on their environmental performance48 or expand upon information provided on

an existing label49.

Various factors shape whether such information is attended to, how it is processed and

perceived, and whether it informs behaviour. For example, prior beliefs act as a ‘filter’ for

whether environmental claims are accepted and shape subsequent attitudes and

behaviour (e.g., Corner et al., 2012). Consumer choices may be habitual, in which case

information processing is minimal; or it may be more deliberative, in which case

information from different sources (e.g., friends, colleagues, official sources) may be

consulted and evaluated (Verplanken & Wood, 2006). The information source, as well as

content, format, and location, will be critical in this evaluation by consumers, with trusted

sources tending to be those that appear to have integrity and competence (Clayton et al.,

2015). Furthermore, environmental information will be only one type of information

which informs consumer decisions; other types include financial, functional, social.

Consequently, the impact of environmental information on subsequent action is indirect

and varies according to multiple psychological and contextual factors. These factors are

summarised in the conceptual model shown in Annex A. Whilst the focus of the evidence

assessment will be on consumers’ purchasing decisions, it is important to acknowledge

the factors which may be utilised or manipulated within the intervention studies to

influence the consumers’ purchasing decisions.

As noted, a range of evidence relating to environmental sustainability information

provision and consumer behaviour is likely to exist, with studies on the effectiveness of

labels being conducted in academia, the public sector and the private sector. However, an

assessment of the evidence from across these sectors and a synthesis of the findings has

not been conducted, to our knowledge. At the same time, the use of information, labels,

48 For example, the European TopTen sites - http://www.topten.eu/

49 For example, the new mandatory China Energy label with a QR code which links to more detailed information on the labelled

product such as including the running costs using local utility rates



certifications and standards for environmental sustainability of products continues to

increase. Therefore, to inform future strategies it is important to ascertain the quality of

the current evidence, the conclusions that can be drawn from it and any existing evidence

gaps.

A primary research question and secondary questions have been determined:

Primary Question

What evidence is there about the effectiveness of providing factual information (including

content, source and format) on the environmental sustainability of a product in influencing

consumer (individual and organisational) buying decisions?

Secondary Questions

What other factors play a role in decisions, which have the most influence, and how do they

interact…?

a) What other product information (e.g. brand, type of product, price) and

consumer characteristics influence purchasing of environmentally

sustainable products?





Critical components of the primary research question were identified by defining the

population, the intervention, the comparator, and the outcome (in line with the PICO

model). As shown in Table 1, these components were defined as “individuals and

consumers”, “provision of factual information on the environmental sustainability of a

product”, “no information provision/alternative information provision”, and “purchasing

behaviour”. It is noteworthy that the intervention component was further divided to allow

for related environmental sustainability terms (i.e. what the information relates to) and

the different types of information to be searched.

Methods and scope

The rapid evidence assessment will follow the method as prescribed in Collins et al. (2015).

Definition of search keywords and search locations

Keywords for the literature search have been developed based on the PICO elements of

the primary research question. Synonyms, antonyms and conceptually similar terms for

these components were determined using the research team’s knowledge and guidance

from the experts who were interviewed as a component of the first part of the project.

See Table 1 for the list of key words. Likewise, a list of existing environmental sustainability

labels were generated through the same processes. The specific ecolabels and

information schemes to be searched are shown in Table 2. As these ecolabels are related

to specific aspects of environmental sustainability and exist in specific forms, the

ecolabels will be searched separately from the “population” and “intervention” terms.

However, they will be combined with the “outcome” terms (e.g. “German Blue Angel” and

behaviour or purchase or procur* etc.) to target evidence related to the research

question.



The keywords were developed in an iterative process of trialling and refining by the

research team such that the results returned from the search are optimised to provide a

comprehensive overview of the available evidence. For instance, it was through this

process that the term “information” was found to be too broad in its meaning to be

entered into the search string without generating too many unrelated returns. As such, it

was determined that “information” will be searched for separately using quotation marks

to link it to the sustainability term e.g. “environmental information”. The draft list were

then reviewed by the steering group.

Search strings will be a combination of the terms for each PICO component and divided

into “Organisation” and “Consumer” as well as by the sustainability terms, with each one

being sequentially interchanged. For instance, in the two examples below, the focus in

both is on the organisation, but in the example one it is then “environment*” whilst in

example two it is “sustainab*”.

Example search string 1: Organisation OR company OR business AND environment*

AND logo OR label OR claim OR guide* OR score OR criteria OR message OR point of sale

OR retail OR warranty AND behaviour OR purchase OR procure* OR choice OR adoption

OR buy*

Example search string 2: Organisation OR company OR business AND sustainab* AND

logo OR label OR claim OR guide* OR score OR criteria OR message OR point of sale OR

retail OR warranty AND behaviour OR purchase OR procure* OR choice OR adoption OR

buy*

The primary question will be the main focus during the evidence search and screening

process; however, information that is relevant to the secondary questions will also be

recorded during the data extraction phase.

Populations Interventions Comparisons Outcomes

Provision of factual

information on the

environmental sustainability

of a product

No

information

provision.

Alternative

information

provision

Purchasing

behaviour

Individual and

organisational

consumers

Sustainability

terms

Information

terms

organis(z)ation

- company

- business

- charity

- third sector

- public sector

- government

consumer

- individual

- public

environment*

sustainab*

recycl*

energy

durab*

footprint

life* (cycle/

span / time)

repair* / repar*

(able/ability…)

logo

label*

claim

guid* (elines

/ance…)

score

criteria

message

point of sale

retail* (er/ed…)

warranty

N/a behaviour/

behavior

purchase

procur*

(ed/ement…)

choice

adoption

buy*

(er/ing…)



- household circular

(economy)

resource

efficiency

ecodesign

“material

efficiency”

biodegrada*

compostab*

bio*

eco*

description

existing labels

(each specific

label)

“information”

term (to be

searched

separately)

*Asterisk used in a search string will mean all forms get searched e.g. environment,

environments and environmental.

Note: All searches to be for the year >1999. (EU level labelling was introduced in the

late 1990s. This time scale is intended to capture early publications whilst maintaining

relevancy to contemporary research on products and labelling.)

Search strings for use on Google will be refined further through the addition of

evidence types: Report or Article or Study or Findings.

Table 1 Components of the primary research question and keywords

Labels

Voluntary product/service ecolabel Stewardship labels

EU ecolabel Forestry Stewardship Council (FSC)

German Blue Angel Energy labels

Nordic Swan Energy label (EU)

US EPEAT Energy rating label (Australia)

TCO Certified China energy label

Korea eco-label Energy star ratings (India)

US EPA Design for the environment Energy label (Thailand)ENERGY STAR (USA

but also international)

Japanese Ecoleaf and Ecomark EnergyGuide (USA)

Ecomark India Carbon labels

Swiss Coop Naturaline Carbon Trust (UK) carbon footprint label

Green seal USA Korea Carbon footprint

Canadian Ecologo Japan Carbon footprint

Environmental choice Thailand Carbon Footprint

Trust Mark (plastic) Carbon Trust (UK)

International Environmental Product

Declaration(EPD) system EU car CO2 label



Building ecolabels Textile labels

International LEED Oekotex 100

International BREEAM Global Organic Textile Standard

US EPA water sense Fairtrade Cotton

Bluesign

Information

Sustainable Procurement Guidance Other information

EU Green Public Procurement Guidance

(GPP)

Top Ten (for energy only)

US EPEAT (IT and consumer electronics) Top Runner (Japan)

Irish Government

Eco schools England

Energy Saving Trust retailer buyer’s guides

(UK)

TopTen professional procurement guides

(EU)

Cradle to Cradle product certification

(USA)

Table 2 Labels and information provision to be included in the search

Development of inclusion and exclusion criteria.

Inclusion and exclusion criteria for evidence were determined by the research team, in

conjunction with the Steering Group, based on the PICO components of the primary

research question and the initial trialling and refining of search terms. The draft criteria

are shown in table 3.

Inclusion and exclusion criteria for REA How implemented in the

REA

Exclusion criteria

Research which has only explored responses to the

information itself (e.g. comprehension, evaluation etc.) and not

its impact on purchase-related decision-making or behaviour.

Using search terms (see table

1).

Not to include product behaviours that are not purchasing

related (e.g. disposal). However these to be separately noted

and citations supplied to Defra/WRAP

Manually during data

selection



Not to include market impacts. However these to be

separately noted and citations supplied to Defra/WRAP

Manually during data

selection.

Studies related to health* Have “not health” in the

search string or manually

during data selection.

Inclusion criteria

Research published between the year 2000 and current date Search criteria (>1999).

Must have researched a form of information which relates to

environmental sustainability AND a product.

Search criteria (see table 1).

Any geographic focus Search criteria (no

geographic focus defined).

Must have assessed a behavioural/decision outcome of the

provision of a form of information.

Search criteria and manually

during data selection.

Table 3 Inclusion and exclusion criteria

* Note: It was agreed with the steering group that food labels would not be included. It

was found that using “not health“ was the most efficient way of eliminating evidence that

related to food. This will be used if there appears to be a high proportion of food focused

evidence within the search results. However, where specific instances of an overlap

between environmental sustainability and health are expected to occur (e.g. organic

labels), then a specific search may be carried out without using the ‘not health’ criteria.

The agreed search protocol will be followed throughout the evidence assessment.

However, the protocol is a working document. If changes to the protocol are deemed

necessary due to unexpected results identified during the evidence assessment, the

Steering Group will be consulted and any protocol changes that are made will be

recorded.

Sources of Evidence

Evidence will be sought from the following sources:

◼ Peer-reviewed literature will be sought using the database platforms Web of Science

and Scopus. These will enable multiple journal databases to be searched

simultaneously using the identified search strings.

◼ Grey literature will be sought through use of internet search engine “Google” (using

identified search strings) and specific searches of relevant institution websites (e.g.

the European Commission, ecolabel.eu). It should be noted that due to the large

number of search results Google is likely to produce, extraction will be limited to the

first 100 results.

◼ Unpublished evidence and grey literature that has been provided by the expert

interviewees and from the project steering group.

◼ Further evidence will be sought through a call for evidence. The content of the call for

evidence will be drafted by the research team before being agreed or amended by

the steering group. The agreed call for evidence will then be distributed through

reviewer contacts, expert interviewees and relevant, existing mailing lists comprising

academics, policy organisations, relevant government departments/agencies, other



stakeholders (e.g. Energy and Social Science Network; Sustainable Development

Research Network), and other publications as suggested by the expert interviewees.

This will specify unpublished evidence as a priority but welcome the highlighting of

relevant evidence from white literature.

Evidence search and search record

The agreed information search protocol will be implemented to conduct the evidence

search in a systematic and transparent manner. A record of searches will be maintained.

The search terms, the date, the database, the number of hits and any date limits for each

search will be tabulated. Details of individual pieces of evidence identified separately (e.g.

from interviewees or from individual websites) will also be tabulated in a separate

spreadsheet with the publication name, date, and source location (including a hyperlink)

and made available to the Steering Group. After the completion of the individual search

strings, results from each search will be combined to create a full list of evidence (with

duplicates removed). Reference managing software, Endnote, will be used to aid this

process.

Screening search results

The selected inclusion and exclusion criteria will then be used to identify the most relevant

evidence amongst the search results. Evidence will be evaluated in two stages:

◼ First stage: Using the title of the evidence, the evidence will be considered against the

inclusion/exclusion criteria. A rating of “clearly relevant”, “clearly not relevant” or

“uncertain” will then be given. A full text will be obtained for evidence evaluated as

“clearly relevant” or “uncertain”.

◼ Second stage: The abstract (or first paragraph) of the full text will then be read and

evaluated against the inclusion/exclusion criteria. Those evaluated as meeting the

inclusion criteria will be selected, noted and used at the extracting evidence stage.

The ratings of the evidence at the second stage will be recorded in an evaluation record

spreadsheet. Likewise, whether the evidence is subsequently included will be recorded.

These spreadsheets will be made available as supplementary information. In order to

reduce bias and increase consistency and objectivity, at the start of each stage a second

member of the research team will independently screen a sub-section (~5%) of the

evidence. The evaluations of each team member will be compared.

Inconsistencies between evaluations will be discussed to ensure that the

inclusion/exclusion criteria are applied consistently and with minimal bias. This process

will be recorded. Furthermore, if an aspect of environmental sustainability information

that was raised by the interviewees as being important is not present within the screened

search results, then the interviewee(s) may be contacted to provide evidence.

Extracting the evidence

The selected evidence will be read in full to extract the information critical to answering

the research questions. See Table 4 for a list of information that will be extracted. All

evidence read at the full text stage will be presented in an Excel file with its extracted data

and critical appraisal (see below). This will form the systematic map or database, which

will then be provided to the Steering Group.



Citation Details

Author(s)

Year of publication

Title of paper

Title of publication (e.g. book, journal,

report)

Vol., Issue, Pages

Nature of study

The type of evidence

The research design used

The population studied

The product-type/sector

Details of the intervention applied

Outcomes measured

Evidence relating to the primary question

(e.g. evidence of impact/response

measured or observed)

Evidence relating to secondary questions

a) What other product information

(e.g. brand, type of product, price)

and consumer characteristics

influence purchasing of

environmentally sustainable

products?

b) What factors have played a role in

successful schemes?

c) What factors have played a role in

unsuccessful schemes?

d) What, if anything, is required in

addition to factual information to

positively influence purchase

decisions?

Table 4 Data extraction form

Critical appraisal of the evidence



To ensure the most relevant and high-quality evidence is given greater weighting in the

synthesis, the evidence will be subject to an appraisal. The appraisal will take into account

the following:

◼ Relevance: Each piece of evidence will be appraised for its relevance to the primary

research question. The relevance criteria are derived from Collins et al. (2015). A

numerical value of between 1 and 3 will be allocated for each criterion, with 1

representing lower and 3 representing higher relevance. An overall, summary score

using the same 1 to 3 scale will then be given based on the evidence’s performance

on all the criteria. See Annex B for the list of relevance criteria.

◼ Robustness: Each evidence type (e.g. experiment, review etc.) has its own criteria.

During the extraction phase, each piece of evidence will be coded for its type and how

well it meets the robustness criteria for its type, scored from 1 (few criteria met) to 3

(all/most criteria met).

[Note, if no information is provided in the evidence for one of the criterion, then a 1

will be awarded to the evidence on that criterion. However, if the study appears

highly relevant then, in a few isolated cases the author may be contacted and asked

to supply the missing detail.]

An overall, summary score using the same 1 to 3 scale will then be given based on the

evidence’s performance on all the criteria. See Annex C for a list of the different

robustness criteria.

◼ Combination: The numerical values for relevance and robustness will be multiplied

for each article to give a combined score (1 = weak evidence and 9 = strong evidence).

Evidence with a higher combined score will be given greater weight in the synthesis.

At this stage, very low scoring evidence may be excluded (to be decided by review

team). Any evidence excluded on this basis will be recorded.

Assigning Confidence and the Creation of Evidence Statements

Using the scores from the critical assessment, a confidence class will be assigned to

descriptions of what the evidence indicates during the synthesis phase. This will provide

an indication of level of confidence with which conclusions can be made from the existing

evidence. The confidence classes and their explanations are shown in table 5.

Class Description

High Evidence from many studies assessed as 6 and/or 1 or more studies assessed as 9

Medium Evidence from one or more studies that have been assessed as 6

Low Evidence from a small number of studies or studies assessed as ≤4

Contested Evidence that differs in its conclusions (present the assessment for each

study/evidence)

Table 5 Categorisation of confidence

Synthesis of the evidence and production of deliverables

All the selected evidence will be reviewed and used to answer the research questions (with

greater weight given to the more relevant and robust evidence) and to report findings on

the adequacy of the evidence base. The synthesis will result in a concise technical report

detailing the following elements:



◼ Description of the volume and characteristics of evidence base: This will include the

types of evidence, research designs, interventions used and outcomes measured.

Gaps and abundance in the evidence will then be highlighted. Results and

conclusions from the critical appraisal will also be discussed.

◼ Description of what the evidence indicates: this will be reported in relation to the

research questions in a narrative synthesis. Tables, figures and graphs will be used to

convey the review and assessment process (e.g. assessment criteria, flow diagram of

included/excluded evidence). In particular, points of evidence convergence and

divergence will be discussed, as well as mixed or uncertain findings. Confidence will

be assigned (according to the relevance x robustness score) and evidence statements

created.

◼ Implications: Indications from the evidence will be related to key policies and

practices (identified with the steering group) to determine if the evidence supports

them. Recommendations for future research or future review processes will be made.

In addition, a two page summary will be produced for publication purposes and a

slide deck will be prepared for the final project meeting to summarise the findings.

References

Collins, A.M., Coughlin, D., Miller, J., Kirk, S. 2015. The Production of Quick Scoping

Reviews and Rapid Evidence Assessments: A How to Guide.

Clayton, S., Devine-Wright, P., Stern, P., Whitmarsh, L., Carrico, A., Steg, L. Swin, J. &

Bonnes, M. (2015). Psychological Research and Global Climate Change. Nature Climate

Change, 5, 640-646.

Corner, A. Whitmarsh, L. & Xenias, D. (2012). Uncertainty, scepticism and attitudes

towards climate change: biased assimilation and attitude polarisation. Climatic Change,

114, 463-478.

Verplanken, B., & Wood, W. (2006). Interventions to break and create consumer habits.

Journal of Public Policy and Marketing, 25, 90-103

WRAP - The Effectiveness of Providing Pre-Purchase Factual Information in encouraging more Environmentally Sustainable Product Purchase Decisions: Expert Interviews and a

Rapid Evidence Assessment 59

Annex A Conceptual model of processes and influential factors in environmental sustainability information influencing consumer

buying decisions



Annex B- Relevance assessment criteria

Relevance of the selected articles

Criteria Low (1) Medium (2) High (3)

The relevance of the

method used to the

REA question*

No intervention

(observational)

Intervention in

laboratory or online

survey setting

Intervention in field

The relevance of the

intervention

assessed*

Environmental

sustainability was

only a small

component of the

information

Environmental

sustainability, in

general, was a large

or main component

of the information

A specific

environmental

sustainability aspect

was the main

component of the

information

Relevance of the

outcome

measurement*

Stated attitudes Stated intentions Purchases (actual or

experimental setting)

Provision of

information

Information was

provided out of

context (e.g. not in

relation to a product)

Information was

provided in relation

to a hypothetical

product

Information was in

relation to a specific

product.

*From the Defra NERC guide to scoping reviews and rapid evidence assessments.



Annex C- Robustness assessment forms

Quantitative: Experimental Design

Title of Evidence Review/Statement:

Title of study reviewed:

Date and authors of study reviewed:

Name of quality assessor:

Date completed:

Criteria Score* Comments

Ge

ne

ral

Are the question(s) and hypothesis/hypotheses

addressed by the study clearly identified?

Are related existing research and theories

acknowledged?

Are sources of funding and vested interests

declared?

Me

tho

do

log

y

Is the sample population used in the study

representative of the overall population that is the

subject of the study and is it relevant in the

context of the evidence statement (e.g. relevant to

England/UK)

Were the experimental/management

interventions well described?

Me

tho

do

log

y c

on

t.

Was the allocation of the

management/experimental interventions random?

If not are confounding factors likely?

Was an adequate control group used? Was this

similar to the population receiving the

management/experimental intervention?

Were outcome variables/measures reliable? I.e.

were outcome variables/measurements objective,

was there any indication that measures had been

validated or subjected to another QA processes?

Were the experimental/management

interventions applied representative in the context

of the evidence statement (e.g. relevant to

England/UK)

An

aly

sis

Were the analytical methods appropriate?

Were the estimates of effect size given or

calculable?

Was the precision of the intervention effects given

or calculable? I.e. Were confidence intervals and or




p-values for the effect estimates given or

calculable?

Su

mm

ary

Overall how well was bias minimised by the study

and how relevant is it to the evidence review/

statement? I.e. how well are the criteria above

met?

*1= Adequate, 2 = Good, 3 = Excellent.

Quantitative: Observational Design





Date completed:


Ge

ne

ral

Are the question(s) and hypothesis/hypotheses addressed by

the study clearly identified?

Are related existing research and theories acknowledged?

Are sources of funding and vested interests declared?

Is the sample population used in the study representative of

the overall population that is the subject of the study and is it

relevant in the context of the evidence statement (e.g. relevant

to England/UK) -

Were the experimental/management interventions applied

representative in the context of the evidence statement (e.g.

relevant to England/UK)

Me

tho

do

log

y

Were the experimental/management interventions well

described?

How were the exposure and comparison groups selected? Was

bias minimised?

Was the selection of explanatory variables based on a sound

theoretical basis?

How well were likely confounding factors identified and

controlled? Were there likely to be any confounding factors that

have not been controlled for that could cause bias?

Were outcome variables/measures reliable? I.e. were outcome

variables/measurements objective, was there any indication

that measures had been validated or subjected to QA

processes?

Were the analytical methods appropriate?



Criteria Score* Comments A

na

lysi

s

Were multiple explanatory variables considered and accounted

for in the analysis?

Were the estimates of effect size given or calculable?

Was the precision of the intervention effects given or

calculable? I.e. Were confidence intervals and or p-values for

the effect estimates given or calculable?

Overall how well was bias minimised by the study and how

relevant is it to the evidence review/ statement? I.e. how well

are the criteria above met?

Su

mm

ary

Overall how well was bias minimised by the study and how

relevant is it to the evidence review/ statement? I.e. how well

are the criteria above met?


Reviews e.g. literature reviews, systematic reviews etc.





Date completed:


Ge

ne

ral Is the aim of the question/topic of the review

clearly identified?

Are sources of funding and vested interests are

declared?

Me

tho

do

log

y

Was a search strategy outlining key words and

sources to be searched identified a priori and used

consistently?

Was publication bias mitigated through the

identification of grey/unpublished literature.

Is there a clear rationale for the inclusion of

studies and is this applied consistently.

Sy

nth

esi

s

Has information from the review synthesised

information in a way that minimised bias.

Do the conclusions relate to the information found

by the review.



Su

mm

ary

Overall how well was bias minimised by the study

and how relevant is it to the evidence review/

statement? I.e. how well are the criteria above

met?




Appendix 2 – Adaptions to the REA protocol

Despite testing during part 1 of the project, difficulties with implementing the search

strings still arose once the full search was conducted and some alterations to the search

protocol had to be made to ensure that the project was manageable and effective within

the scope of the REA and the research question. These changes and their rationale are

outlined below.

Database searches

Databases of peer reviewed literature were searched using Scopus and Web of Science.

Following the full instigation of the search protocol, it was determined that the original

search strings (Protocol Version 4) were inefficient and returning too many results to be

screened within the scope of a REA; a moderately high number of results for one search

string was then compounded by the overall high number of search strings that were

necessary to capture all the keywords of interest. As such, new search strings were

developed which utilised the databases’ proximity Boolean operators (W/x in Scopus and

NEAR/x in Web of Science). This forces the search to only show results where the

keywords appear near to each other. This increases the specificity and effectiveness of

the search by ensuring the words of interest are appearing close together (as opposed to

“AND” which allows the words to appear anywhere). Whilst some of the search strings still

returned high numbers of results, it was felt that, given the breadth of the research

question, further refinement might not be possible at the search stage.

Selecting the number of words that the terms must be within or near requires

consideration of the likely phrases that might be encountered in the relevant evidence.

For this search W/1 and NEAR/1 was adopted. To ensure that this was not overly strict,

the first 200 results for the organisational and individual search strings that used a more

relaxed “W/5” in Scopus were compared to the W/1 in Scopus. Where a relevant piece of

evidence was identified in the W/5 results, the W/1 results were checked to see if it was

present. In all cases they were which gives confidence that the W/1 was efficiently

capturing relevant evidence.

Google searches

For grey literature, Google was used to search the internet. Due to the uniqueness of the

Google algorithms and their move towards using “native language” as opposed to

Boolean operators, the pre-determined search strings were ineffective in Google.

Therefore, following consultation with the steering group, new search strings using fewer

of the keywords were adopted. Furthermore, a specification for .pdf files was added. This

was use in an attempt to focus on evidence reports as opposed to websites. To keep the

returned evidence to be screened at a manageable number for screening, only the first

100 results were captured for each search. Of these 100, approximately the first 30 will

be screened (in anticipation that some search terms results will have greater relevance

than others, more or less than 30 may be screened based on the research teams’

judgement).



Changes to Keywords

The terms “Bio*” and “Eco*”, added during the interim meeting, proved too broad when

searched. Consequently, Bio* was dropped from the list of sustainability terms and the

Eco* search string had the additional NOT criteria of “economi* and “economy” added.

“Life*” was also found to be too broad and so “Lifecycle”, “lifespan“ and “lifetime” were

specified in the search string instead.

Label searches

It was intended that the specific label searches would be conducted in Scopus, Web of

Science and Google, however, due to project time restrictions, the labels were only

searched for in Scopus and Google.

In addition to these search related changes the confidence statement classifications were

adjusted as noted in table 2 of the main report.



Appendix 3 – Questions for expert interviews

1. In the context of our primary research question:

“What evidence is there about the effectiveness of providing factual information

(including content, source and format) on the environmental sustainability of a

product in influencing consumer (individual and organisational) buying decisions?”

a) Please describe the relevant areas you have worked on:

[Note: Information type (waste reduction, lifecycle, energy, ecolabel, carbon label,

procurement advice etc) and sector (electronic and electrical, textile, others…) ]

b) Please describe any relevant current work by other people/organisations,

published or unpublished, especially any ‘grey literature’ (i.e. produced by

organizations outside of the traditional commercial or academic publishing and

distribution channels) that we might not otherwise find:

2. In the context of our secondary research questions, please provide your insights

and any references to relevant research (published or unpublished) or

refinements to the questions themselves:

What other factors play a role in decisions, which have the most influence, and how

do they interact …?

a) Other product information (e.g. brand, type of product, price) and consumer

characteristics influence purchasing of environmentally sustainable products?





e) To what extent is there divergence or convergence in buyers’ assessment of

environmental information versus its behavioural impact?

f) Is there any evidence of unintended consequences?

3. Which specific labels/schemes do you think we should include with reference to

the following audiences:

a. Organisational purchasers

b. Individuals

4. Please provide details of any textile related environmental information schemes

you are aware of:



5. Please provide details of anyone else you suggest we interview:

6. Please provide suggestions on how to judge the robustness/significance of

evidence, in particular any methods you consider more robust than others:

7. How would you suggest we best publicise a call for evidence (if issued)?

8. Would you like to get interim feedback on our findings?



Appendix 4 – Collated responses by experts to interview

questions and summary

Collated responses

The collated response of interviewees to our interview questions is shown here. (Note

that not all questions were answered by all interviewees.)

Role of information and other factors in influencing consumers’ decision-making

◼ The effect of information on behaviour depends on the context, in particular the

product bought. For example the experience from buying appliances or choosing

renewable supply of electricity do not transfer to buying cars

◼ Consumers’ behaviour depends on attitudes – for example on level of environmental

concern or in the importance they place on what happens in the future

◼ For cars, consumers first chose the model/class of car they are interested in – and

the environmental impact is not taken into account in this decision. Then within the

class, various factors are considered including, sometimes, sustainability

◼ Other factors considered include: price; safety; functionality; quality; running costs;

how long a product will last.

◼ For energy using appliances the scope for whole life payback is less than it used to be

- the ‘it will pay you back’ argument for energy efficient goods is becoming weaker –

when the difference becomes small consumers are not motivated by it.

◼ Durability was found to be much more important for large white goods and less

important for clothes and technology (high technological rate of turnover durability).

An unusual trend observed was that there was a relatively higher willingness for

second-hand replacement rather than a new phone upgrade to replace a broken

smartphones

◼ Circular economy considerations are less important for clothes, but a jacket is more

likely to be repaired if there’s an emotional connection

◼ For cars the decision isn’t generally made by an individual on their own – it is made

within a family, with other family members’ views taken into account

What factors have played a role in successful schemes?

◼ Presentation:

o Simplicity of presentation of information so that it can be understood

intuitively and not require mental processing (for household schemes)

o Simplicity of message: those (for householders) which have a simple

message (eg FSC)

o Consistency and comparability of information

o Potential for negative signals: ‘don’t buy’ may be more powerful than a

positive signal

o Schemes that allow choice editing by purchasers (eg EPEAT and TopTen)

◼ Policy:

o Coverage: A regulatory mandate so that all products have to provide the

information/carry the label.



o Combination with minimum standards or any package of policies that

reinforce each other.

o Incorporation of schemes within requirements for public procurement

o Combination with a financial incentive: increases influence directly and

also provides a signal that the Government is serious about the topic –

they are not just providing information they are prepared to put money

into it.

◼ Credibility:

o Endorsement: by a respected authority (eg EC or national government)

o Verification: high credbility provided by certification and ongoing

verification

◼ Traceability:

o For professional procurers it helps to have traceability of the

sustainability of the purchase to show that they are meeting their

organisation’s specific sustainability goals.

◼ Promotion:

o Those which are persistently and consistently promoted

◼ Duration:

o Schemes which are long established build recognition and trust

◼ Motivation:

o Schemes driven by demand from consumers, or manufactures who want

to create a market advantage by using sustainable labels, may be more

effective at motivating the creation of sustainable labels than

government.

What factors have played a role in unsuccessful schemes?

◼ Presentation:

o Too much information or information that is too complex

o Linking to a distant, complex or abstract problem is less effective than

something more concrete and closer to hand (eg climate change labels vs

dolphin friendly tuna label).

o Where what is measured is not meaningful to customers (eg some carbon

labels)

o Consistency and comparability: Schemes that use inconsistent

benchmarks or make it difficult to assess or compare between models.

◼ Coverage:

o Non-mandatory schemes can be weaker - when some products don’t

have information it creates doubt around the validity of the information

that others have.

o Overlapping labels (ie labels relating to the same kinds of issues on the

same product eg EU ecolabel on products with the EU energy label) have

reduced impact

o Applicability: Schemes that were designed for one country and transfer to

another without customisation.



◼ Credibility:

o Schemes that have been associated with hypocrisy or unreliability or

otherwise lack credibility

◼ Promotion:

o Schemes that are not promoted clearly – that are associated with mixed

messages

◼ Ambition / stringency:

o Schemes which set the bar unrealistically high so no or very few products

qualify

What is required in addition to factual information to positively influence purchase decisions

Required factors were limited to:

◼ Credibility:

o Credibility of the information (consistently listed as essential)

◼ Presentation:

o Design is important – information must be provided in a form people can

use.

◼ Confidence:

o Consumers trusting themselves to be able to make the decision.

However, suggestions for other factors that are not required, but which can help

included:

◼ Cultural:

o Favourable public opinion towards the sustainable issue or innovation –

supported by coverage of the issue in the media

o Social norms can be effective – people can be influenced by what other

people are (reported) as doing.

o The sustainability feature being seen as ‘cool and trendy’ by consumers

◼ Policy:

o Financial incentives can help, if carefully designed.

◼ Delivery:

o Social media can be an important tool for communication – act as a

gateway to information

o Gamification through apps (teach people about the sustainability of

products/the labels)

◼ Presentation:

o How easy the ‘green’ product is to find – how it is presented in the

shop/online can make a difference. For example, if a retailer has an own

brand product which is labelled they will display this prominently and this

will sell better

Divergence or convergence in buyers’ assessment of environmental information versus its

behavioural impact



◼ What people think they want from information and what they respond to are

different (frequently they say they would like more information, but then negatively

react to large amounts of information). Consumers want an easier solution than

labels and information – if they can trust a brand/shop is sustainable across the

board, then they prefer that.

◼ A number of interviewees recognised the gap between intention and behaviour:

o The importance of the gap may depend on the product. Pleasure based

purchases, for example TVs, are less susceptible to an energy efficiency

message than more functional products such as freezers.

o Some studies found a clear link between self-declared attitude and

behaviour, and that it was easier to influence those who were already

environmentally minded.

◼ Labels can influence behaviour quite directly:

o Eco-labels can facilitate an intention becoming a behaviour and so be a

tool to bridge the intention-behaviour gap.

o Labels can serve to make sustainability a factor under consideration at

point of purchase, increasing the likelihood people will prioritise this.

o Information may have an indirect influence by making people aware that

there is a problem that caused the need for a label. The more information

is available and promoted, the more people will be exposed to the

arguments and understanding of the labels.

o Upstream sustainability information is often not a concern for consumers.

They focus on the performance or usage characteristics (eg. the energy in

use).

Evidence of unintended consequences

It is possible that in the drive to achieve environmental sustainability, there are

compromises in other aspects, for example moral or ethical. Whilst one problem may be

solved, another may be created.

◼ Neglect of unlabelled aspects: Labels/information (and the calculations behind

them) may lead to a focus on one sustainability issue of a product to the neglect of

others. For instance, indicating that electric vehicles are low emission only takes into

account their point of use and does not account for the (energy and emission

intensive) production of the battery and so calling electric vehicles “low emission”

may mislead consumers.

◼ Disproportionate focus on aspects vs impacts: For example, the focus on energy

efficiency, rather than energy use, in the EU energy label (and Ecodesign regulations)

for washing machines – as higher energy efficiency is easier to achieve with larger

machines this led to an increase in the capacity of washing machines sold despite

consumers using the same load size.

◼ Unintended wider positive influence: There can be a ‘halo’ or positive ‘spillover’

effect from labels – a product which is labelled for a particular feature may be

assumed by consumers to be higher quality in other respects. Information or labels

on one product or issue may lead to changed purchasing behaviour with other



products or issues. Information can reinforce other policies even if it has a limited

effect in isolation.

◼ Negative perception of information provision: The study for the EU on resource

efficiency found that there were no unintended consequences from giving

information on reparability – this was not interpreted by consumers as implying that

the product was easy to break.

◼ Information overload: Too many labels may put consumers off.

◼ Negative association between labels: It is possible that weak or ineffective labels

may ruin the reputation of other labels.

◼ Rebound effect: Some interviewees pointed to the rebound effect or moral licensing

(for example driving further in a low carbon vehicle) as a concern; others felt that its

impact was overstated and that it is not a significant problem.

Summary

The interviewees represented a wide range of organisations and experience relating to

environmentally sustainable product purchase decisions: some had been involved

through specific projects, for others this has been the work of most of their career; some

had worked on or studied established schemes such as ecolabels and energy labels,

others in newer areas such as the circular economy. This diversity provided a wide range

of responses to all the research questions.

The interview findings have contributed to the development of the draft protocol (that

has been drafted in parallel with the interview process) which will be used to undertake

Rapid Evidence Assessment (REA) on this topic. They have also provided direct evidence,

in the form of white and grey literature, were included in the REA.

It is difficult to condense such a rich response to a few key points, but we feel that some

highlights can be drawn from the findings:

Considerations for successful schemes:

◼ Presentation (simplicity, consistency, lack of abstraction/meaningful, comparability)

◼ Policy (mandated for comprehensive coverage, combination with financial incentives,

procurement requirements and other policies)

◼ Credibility (endorsement, certification and verification)

◼ Traceability

◼ Promotion

◼ Long duration

◼ Demand driven schemes

◼ Avoidance of overlap

◼ Tailoring to geographical / cultural context

◼ Appropriate level of ambition

Intention vs behaviour: This will vary depending on the product (e.g. pleasure vs

practical products), and it is easier to influence those who are already environmentally

minded.

Unintended consequences of information provision can include:



◼ Neglect of unlabelled aspects and disproportionate focus on aspects vs impacts

◼ Unintended wider positive influence

◼ Information overload

◼ Negative association between labels

◼ Rebound effect

Features of robust studies include:

◼ Wide range of information types and sustainability aspects addressed

◼ Incentivised choice experiments

◼ Focus groups

◼ Simulation of reality

◼ Long duration

◼ Avoidance of a focus only on intention





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purchase-information

http://www.wrap.org.uk/providing-pre-purchase-information

http://www.wrap.org.uk/providing-pre-purchase-information

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