Integrating Disability Census Microdata: What is available from IPUMS-International? (all census documentation used in this paper is available.

Integrating Disability Census Microdata: What is available 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 comparability issues in censuses with

respect to disability (4 slides)• IPUMS integration of documentation and

microdata (4 slides)• IPUMS Integration of disability microdata (4

slides) • Analysis of global rates of disability in IPUMS

samples with discussion of methodological issues regarding comparability (9 slides)

• Conclusions (2 slides)

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:Integration of census microdata and Integration of census microdata and

documentationdocumentation

What is IPUMSI?• Global collaboratory of universities, National

Statistical Offices, and international research institutes

• Purpose: 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.

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 .

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

Microdata Availability• 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 than 5% (e.g. China).

• Samples for 6-8 countries released annually.– Fifty eight NSOs have entrusted microdata to the

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

Integration of Disability in IPUMSIntegration of Disability in IPUMS

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, use of 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– notwithstanding considerable international effort at

standardization

Example of comparability discussion in IPUMSExample of comparability discussion in IPUMS

For sample counts, first For sample counts, first click codes, click codes, then then case count viewcase count view (careful: these are (careful: these are unweightedunweighted counts) counts)

Analysis and Discussion of Global Disability Analysis and Discussion of Global Disability FrequenciesFrequencies

( ( 2000’s census round data only in 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• In Table 1 (next slide), 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 reference period, reporting and phrasing of question(s)

– Reference population:

• Age filter in type 4 disability (EMP) – Chile 1982 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

Conclusions, 1:

• IPUMS – A readily available source of census data on disability

– Caution about comparisons across countries and over time.

– Current 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

– Perhaps data for 2010 round of censuses will be more readily comparable

Conclusions, 2:

• Whatever concepts, nomenclatures, and coding schemes are used in 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 to suggest enhancements not only the treatment of

disability variables but also to the IPUMS system as a whole.

Thank you