Rating scale

Rating scales

By-DHEERAJ KUMARM.A. 3rd semester

RATING SCALES

A rating scale is a measuring instrument that requires the rater or observer to assign a rated object to categories or continua that have numerals assigned to them.

Rating asks the respondent to estimate the magnitude or the extent to which some characteristic exists.

Is a measurement task that requires respondents to estimate the magnitude of a characteristic or quality that a brand, store, or object processes.

TYPES OF RATING SCALESCategory rating scale

Graphic rating scale

Graphic scale with pictureresponse categories

Method of Summated Ratings:Likert rating scale

TYPES OF RATING SCALES

Composite rating scale

Semantic differential scale

Numerical rating scale

Stepel scale

TYPES OF RATING SCALES

Check list

Forced choice rating scale

Percentage rating scale

Balanced or Unbalanced Rating Scale

Category Rating Scales The category rating scale presents the observer or judge with several categories from which he picks the one that best categorizes the behavior or characteristics of the object being rated.

The simplest rating scale contains only two response categories: agree/disagree.

CATEGORY RATING SCALES

If response category is expanded—

It provides the respondent with more flexibility in the rating task. Even more information will be provided if the categories are ordered according to a particular descriptive or evaluative dimension.

Example of Category Scales

If the researcher tries to represent something that is truly bipolar (yes/no, female/male, member/nonmember, and so on) with more than two categories, error may be introduced.Question wording is an extremely important factor in the usefulness of these scales . Following Table shows some common wordings used in category scales.

In buying food for my family, price is no object. Strongly Disagree Uncertain Agree Strongly Disagree Agree (1) (2) (3) (4) (5)

Selected Category Scales Quality Excellent Good Fair PoorVery good Fairly good Neither good nor bad Not very good Not good at allWell above average Above average Average Below average Well below average ImportanceVery important Fairly important Neutral Not so important Not at all important InterestVery interested Somewhat interested Not very interested SatisfactionCompletely Somewhat Neither satisfied Somewhat Completelysatisfied satisfied nor dissatisfid dissatisfied dissatisfiedVery satisfied Quite satisfied Somewhat satisfied Not at all satisfied FrequencyAll of the time Very often Often Sometimes Hardly everVery often Often Sometimes Rarely NeverAll of the time Most of the time Some of the time Just now and then TruthVery true Somewhat true Not very true Not at all trueDefinitely yes Probably yes Probably no Definitely no UniquenessVery different Somewhat Slightly different Not at all different differentExtremely unique Very unique Somewhat unique Slightly unique Not at all unique

The Likert Scale

A measure of attitudes designed to allow respondents to rate how strongly they agree or disagree with carefully constructed statements, ranging from very positive to very negative attitudes toward some object.

A Likert scale consist of a series of statements each followed by a series of response alternative for the respondent to express himself or herself about the statement.

In a Likert scale the most common number of alternative is five because it often respondents a sufficient range of choice without requiring unnecessarily minute distinctions in attitudes

The Likert Scale……

strongly agree, agree, uncertain, disagree, and strongly disagree

The number of alternatives may range from three to nine. In the following example, from a study of food-shopping behavior, there are five alternatives :

In buying food for my family, price is no object. Strongly Disagree Uncertain Agree Strongly Disagree Agree

(1) (2) (3) (4) (5)

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The Likert Scale……….

Concept/ConstructOperational definition DimensionsPurpose/objectivePopulation

Constructing a Likert scale


Begins by developing a series of statements relating to the variable being measured by using general criteria for statement .

How much item should developed?

Three times more the number of scale desired for the final scale.

Generation of item pool


General criteria for generating item Should be -Simple ,clear, and direct.Should be unambiguous.Must strike a balance between generality and specificity in writing items.Should avoid constructing leading items.Should not be factual.Avoid items which require respondents to recall information from the distant past. Avoid double-barreled items, which is one item asking two questions. (height &weight) Should not use word like often, always, never, some time etc.Should avoid double negative items……………………..


Items screening On the basis of expert advice- On the basis of statistical analysis—Discrimination power index/score - essentially tell usThe degree to which each item differentiates betweenRespondents with high score and respondents with low score on the overall scale.Correlational technique/internal consistency item discrimination index(r 0.15≤) & Method of testing `the significance of difference between two proportions orpercentage (1≤)

Researchers assign scores, or weights, to each possible response. In this example, numerical scores of 1, 2, 3, 4, and 5 are assigned to each level of agreement, respectively.

REVERSE RECODING

If a statement is framed negatively the numerical scores would need to be reversed.

For example-

“I carefully budget my food expenditures”

The Likert Scale…..

A method of making sure all the items forming a composite scale are scored in the same direction. Negative items can be recoded into the equivalent responses for a non-reverse coded item.

For a typical 1–5 scale, the formula of REVERSE RECODING

REVERSE RECODING

Xnew value = 6-Xold value

Reliability of Likert scale

Cronbach`s/Coefficient alpha(α)

α = (n/n-1)×{ΣDi-Σ(SDi2) }/SDi

2

It is the most popular multiple-item formats because of the many advantages it processes.

The Likert Scale……ADVANTAGES

Data produced by Likert scale at least ordinal level and many consider them Interval level, which enables us to use more powerful statistical procedure than with nominal data.Likert measure are fairly straightforward to construct.

The Likert Scale……DISADVANTEGES

One must be careful in interpreting a single score based on a Likert Scale because it is a summary of so much information (separate response to a number of items ).

To generate unambiguous and unbiased item.

COMPOSITE SCALESA way of representing a latent construct by summing or averaging respondents’ reactions to multiple items each assumed to indicate the latent construct.

A Likert scale may include several scale items to form a composite scale. Each statement is assumed to represent an aspect of a common attitudinal domain.

Likert Scale Items for Measuring Attitudes toward Patients’ Interaction with a Physician’s Service Staff

COMPOSITE SCALES…..

1. My doctor’s office staff takes a warm and personal interest in me.2. My doctor’s office staff is friendly and courteous.3. My doctor’s office staff is more interested in serving the doctor’s needs than in serving my needs.4. My doctor’s office staff always acts in a professional manner.

Item 3 is negatively worded and therefore it is reverse coded , prior to being used to create the composite scale.

Example-

Semantic DifferentialA measure of attitudes that consists of a series of seven point rating scales that use bipolar adjectives to anchor the beginning and end of each scale.Bipolar adjectives—“good” and “bad,” “modern” and “old fashioned,” or “clean” and “dirty” etc.

Respondents are instructed to check the place that indicates the nearest appropriate adjective.

Scoring of the semantic differentialFrom left to right, the scale intervals are interpreted as:

“extremely modern,” “very modern,” “slightly modern,” “both modern and old-fashioned,” “slightly old-fashioned,” “very old-fashioned,” and “extremely old-fashioned”: 7 6 5 4 3 2 1

Modern - - - - - - - Old fashioned”

Semantic differential scale…..

The semantic differential technique originally was developed as a method for measuring the meanings of objects or the “semantic space” of interpersonal experience.

Scoring of the Semantic Differential….To reduce response set (i.e., a subject responding in a consistent manner that does not represent his or her “real” sentiments) several score weights are reversed. For example:

(a) Eager (7)……………….. Indifferent (1)

(b) Useless (1)………………Useful (7)

Scoring of Semantic Differential…….. Which type of data it will produce?This item format produces interval level data and parametric statistics may be applied.All of the Measures of central tendency and MCV`s are appropriate.The number and percentage of respondents endorsing each response option is also reported.

Advantages and disadvantages of semantic differential scale

SDs are much easier and less time consuming to construct than other scales. Adjective pairs are easier to develop than are unambiguous and unbiased statement. Adjective pairs from prior studies are more readily adaptable to new studies because of their general and nonspecific nature.Identifying the abstract dimensions tapped by the adjective pairs is somewhat subjective and judgmental.The validity of the conclusion drawn is only as good as the judgment of those who identify the dimension.

Numerical ScalesAn attitude rating scale similar to a semantic differential except that it uses numbers, instead of verbal descriptions, as response options to identify response positions.

Now that you’ve had your automobile for about one year, please tell us how satisfied you are with your Ford Taurus.

Extremely Dissatisfied 1 2 3 4 5 6 7 Extremely Satisfied

Stapel Scale

A simplified version of the semantic differential scale in which a single adjective or descriptive phrase is used instead of bipolar adjectives.

Characteristics1. The scale measures both the direction and intensity of the

attribute simultaneously.2. It has properties similar to the semantic differential. Example:

Model A-3 -2 -1 Durable Car 1 2 3-3 -2 -1 Good Fuel Conaumption 1 2 3

Response BiasSource of response bias-Response set Response pattern anxietySocial desirability effect

Hard to attach a verbal explanation to response

Visual impact, easy for poor readers

Choose a visual picture 8. Graphic scale-picture response

No standard answers Visual impact, unlimited scale points

Choose a point on a continuum

7. Graphic scale

Endpoints are numerical, not verbal.

Easier to construct than semantic differential

Choose point on scale with 1 center adjective

6. Stapel scale

Bipolar adjectives must be found, data may be ordinal, may be interval

Easy to construct, norms exist for comparison, e.g. profile analysis

Choose points between bipolar adjectives on relative dimensions

4. Semantic differential and numerical scales

Hard to judge what a single score means

Easiest scale to construct Evaluate statements on a 5-point scale

3. Likert scale

Ambiguous items, few categories, only gross distinction.

Flexible, easy to respond Indicate a response category

2.Category scale

1. Simple attitude scaling

Disadvantages Advantages Subject must:Rating Scale

Characteristics Different Types of Rating Scales

Issues Related to Rating Scale

1. Whether to use single or index measure.2. Whether to use a ranking, sorting, choice, or rating

scale.3. Whether to use monadic or comparative scale.

• Monadic rating scale is one in which respondents evaluate an object in isolation

• Comparative scale s one in which the object is evaluated in relation to other objects

• Construction and labeling is different for monadic and comparative scales

4. Whether to use category labels or not.5. If the decision is to use category labels, what labels

to use.

Issues Related to Rating Scale

6. Number of response options (scale categories) to use, i.e whether to use 2, 3, 4, 5, etc response categories• In general, the larger the number of categories the more sensitive the

scale is; but also the more difficult it is for respondents to answer

7. Whether to use balanced or unbalanced scale.• A balanced scale has an equal number of points to the left and right

of a mid-point. An unbalanced scale has more response options on one side than the other

8. Whether the scale should force choice among the response categories, i.e should the scale contain a “neutral” or “don’t know” category.

•Thank You

Education

Rating scale