Integrating Disability Census Microdata: What is accessible

from IPUMS-International?www.ipums.org

(all census documentation used in this paper is available at the IPUMS site)

Krishna Mohan Palipudi Robert McCaa

Minnesota Population CenterUniversity of Minnesota

USA

Outline• Overview of the IPUMS-International

census microdata integration project

• IPUMS integration of documentation and microdata

• IPUMS Integration of disability microdata

• Analyze global measures of disability prevalence and discuss methodological issues of comparability

Overview of comparability issues in censuses Overview of comparability issues in censuses with examples for:with examples for:

Portugal: 1991, 2001Portugal: 1991, 2001Uganda: 1991, 2002Uganda: 1991, 2002

Note: we are not criticizing methods used by Note: we are not criticizing methods used by the census authorities. the census authorities.

Comparability of disability statistics

• Major obstacles to comparative analysis—both across countries and over time—data:– Reliability– Comparability

• Particularly acute for disability estimates• Censes is the only source, for many countries,

of: – complete population counts on disabilities– social and economic characteristics over time

Portugal 1991: disability as a category of economic activity question

2001

1991

Portugal

2001

2001

8. DO YOU HAVE ANY DISABILITY?♦ No …….. 1 GO TO 9♦ Yes, indicate the type:♦ Hearing ……..……... 2♦ Visual …..………….. 3 ♦ Physical ……….…... 4 ♦ Mental .…..………… 5♦ Cerebral palsy ……. 6♦ Other……………...…7

1991

Uganda1991

2002

IPUMS-International:IPUMS-International:

What is IPUMSI?• Global collaborator of universities, National

Statistical Offices, and international research institutes

• Preserve, integrate and manage access to high-density census microdata samples

• Funded by National Institutes of Health and the National Science Foundation of the United States, since 1999

• Endorsed by National Statistical Offices (NSO’s) in seventy-two countries, 60%+ of the world’s population.

Microdata Accessibility• Fifty eight NSOs have entrusted microdata to

the MPC for a total of 172 censuses (June 2007).

• Currently, integrated samples are accessible from www.ipums.org/international for – 26 countries, – 80 censuses and – 202 million person records.

• Ten percent samples for most, some 5%, a few are less.

Documentation• Archive, scan and disseminate census documentation

(see congress satchel for CD; also internet). • Forms for 765 censuses for most countries may be

downloaded at www.hist.umn.edu/~rmccaa/IPUMSI/enumform.htm,

• Complete census documentation– In official language– And English translation

• Dynamic Metadata System facilitates comparison of any combination– Of countries– Of census years

Scroll down to see comparability discussionScroll down to see comparability discussion

For sample counts, For sample counts, click case count viewclick case count view (careful: these are (careful: these are unweightedunweighted counts) counts)

IPUMS Integration Methods• Adopt coding schemes, nomenclatures and

classifications, based where possible on the United Nations Statistics Division’s Principles and Recommendations for Population and Housing Censuses (first 1998, now 2006) and other international standards.– For disabilities (2006), see paragraphs 2.341-370

• Goals:– easy to use for comparisons across time and space. – provide the lowest common denominator of detail that

is fully comparable– Additional detail .

Integration of Disability in IPUMSIntegration of Disability in IPUMS(2 slides)(2 slides)

Comparability between countries

• IPUMS must use post-harmonization technique (Rijckevorsel, 2001).

• Therefore… it is difficult to integrate microdata on disability that are comparable cross-culturally and even between censuses.– lack of consistency in terms, definitions and

classifications.

IPUMS strategy: disability• yes/no integration classification scheme for each

type: – disabled, blind, deaf, mute, lower extremities, upper

extremities, mental, psychological, personal care, mobility, public transportation, work, etc.

• Access to original nomenclatures in the “unharmonized” variables. – “harmonized” may be useful for comparison– “unharmonized” is most useful for analyzing a single

census.• Researchers are urged to use the “unharmonized

variables” for disability--due to the great variety of phrasings and notwithstanding considerable international effort at standardization

IPUMS-International:IPUMS-International: 2000’s census round only used for this

paper.

Comparability between countries• With regard to the questions used, differences are due

to – the type of questions used, i.e., whether impairment,

activity limitations or participation based– the wording of the questions with regard to terms

used– the scope of the questions in terms of the number of

disability items included– the reference period that was considered to

determine a persons disability status– reference population– de facto/de jure population counts

Comparability between countries• For this paper, disability in IPUMS samples are broadly

classified into 4 types.– Type 1 (PRES = Present): A generic/general question on

presence of a condition/impairment combined with items on participation and activity limitations.

– Type 2 (P&L=Present & List): A generic/general question on presence of the disabled or handicapped in the household followed by a list of impairments and/or disabilities.

– Type 3 (LIST): A checklist of impairments from which respondents are required to choose.

– Type 4 (EMP=Employment): Employment or work related questions used to assess the disability.

P&L

Pres

EMP

List

Differences between countries(2000 round censuses)

– Ecuador (2001) – permanent difficulty in doing an activity that is considered normal, due to irreversible effects from an incurable congenital or acquired disease

– Philippines (2001) - any restriction or lack of ability (resulting from an impairment) to perform an activity in the manner or within the range considered normal for a human being

– Portugal (2001) – any loss or change in a structure or in a psychological, physiological or anatomic function. It is a permanent disability and if have more than one disability, state the one with greatest degree of incapacity

– South Africa (2001) - serious condition that prevented the respondent’s full participation in life activities such as education, work and social life

– Uganda (2002) - a long term physical condition or health problem lasting 6 months or more

• Further compounded by reporting and questions used

– Reference population:

• Different in type 4 disability (EMP) – Chile 1982 are 15+;

– Ecuador 1990 (8+);

– Portugal 1981-91 (12+);

– Venezuela 1971 (15+);

– Venezuela 1981 (12+).

• Rwanda 2002 – non-visitors

• South Africa 1996 – Private households.

– Definitions influenced by the cultural practices and perceptions in each country

Comparability between countries

• Uganda (1991) – “is there anyone who was in the household on census night disabled and the nature of disability?”

• Uganda (2002) – “does (name) have any difficulty in moving, seeing, hearing, speaking or learning, which has lasted or is expected to last 6 months or more?”

• Portugal (1981, 1991) – derived from employment variables and reports all the persons 12+ who are permanently incapacitated/unable to work during the week before census

• Portugal (2001) - Do you have any disability? Physiological or anatomic function. This question only applies to persons with a permanent disability on census night. If they have more than one disability, the main one with greatest degree of incapacity is reported.

Comparability between censuses within a single country—recall

Uganda and Portugal

• Observed a significant deference in prevalence between two samples Uganda and Portugal.

• In Portugal, disability was measured by administering a straight question, where as in 1981, 1991 samples disability is derived from the employment questions and both samples differ significantly in the content and magnitude.

• In Chile the content and wording was same for the samples in 1992 (2.14%) and 2002 (2.2%).

• In Philippines (1990, 1995, 2000), all the three samples have administered 2 questions each and we can easily compare the time series data in Philippines.

Comparability between censuses within a single country

• We examined differentials in disability estimates across various socioeconomic and demographic subgroups over time in most comparable census samples.

• Explains the changing inequalities in disability estimates using concentration index.

• These are away from the context of today’s talk.

Comparability between censuses within a single country

Conclusions

• Just before challenges for the 2010 round.• IPUMS data are a useful and important source on

disability that provides information on frequency and distribution of disability in the population across countries and over time at national and regional/province level if used sensibly.

• Prevailing scheme of harmonization, though the estimates vary by question type and definitions used, is useful in comparing time series data to get a better picture on variations.

Conclusions• Whatever concepts, nomenclatures, and coding

schemes are used in the census operations for the 2010 round of censuses, IPUMS will retain the originals nomenclatures in the “unharmonized” variables.

• For the integrated variables an attempt may be made to go beyond the yes/no classification to a more detailed composite coding scheme.

• Official statisticians and researchers are invited to use the IPUMS data and documentation and make suggestions to enhance not only the treatment of disability variables but also the IPUMS system as a whole.

Thank you