1. October 151 Measuring Disability in Censuses and Household Surveys Mitchell Loeb National Center for Health Statistics, USA for the Washington Group on Disability Statistics

2. October 152 This presentation will cover: Disability definition and the International Classification of Functioning, Disability and Health – ICF Disability measurement and the Washington Group on Disability Statistics – WG An example of disability prevalence measurement from a recent Zambian survey

3. October 153 Our understanding of disability has changed: from: a medical definition – based on a medical condition as an individual pathology to: a concept based on the consequences of diseases; on functional capacity and social participation

4. October 154 Moving from Concept to Definition to Measurement: The Conceptual Model ICF selected as the conceptual model: Common point of reference Common vocabulary Does not provide an operational definition or a way to measure the concepts

5. October 155 Health Condition (disorder/disease) Body Function & Structure (Impairment) Activities (Limitation) Participation (Restriction) Environmental Factors Personal Factors Source: World Health Organization, 2001 The ICF Model

6. October 156 Moving from Concept to Definition to Measurement: The Definitional Paradox There is no single operational definition of disability Different operational definitions lead to different estimates The question you are trying to answer (the purpose) will determine which definition to use

7. October 157 Purpose of Data Collection 3 major classes of purposes at aggregate level Service Provision Monitoring functioning in the population Assess equalization of opportunities 2 criteria for selection of a purpose Relevance—particularly for policy makers and program officials Feasibility

8. October 158 Purpose: Equalization of opportunities Seeks to identify all those at greater risk than the general population of experiencing restrictions in social participation, for example in employment, education or civic life Disability as a demographic

9. October 159 Moving from Concept to Definition to Measurement: Measurement of equalization of opportunities Locate the definition of disability at the most basic level of activity/participation in core domains Defined as the ability or inability to carry out basic actions at the level of the whole person (i.e. walking, climbing stairs, lifting packages, seeing a friend across the room) Connection between ‘disability’ and participation can be made during data analysis

10. October 1510 Health Condition (disorder/disease) Body Function & Structure (Impairment) Participation (Restriction) Environmental Factors Personal Factors Source: World Health Organization, 2001 Locating Risk in the ICF Model ?

11. October 1511 Possible question options Mobility Walking Climbing stairs Bending or stooping Reaching or lifting Using hands Sensory Seeing Hearing Communicating Understanding Speaking Cognitive functions Learning Remembering Making decisions Concentrating Emotional functioning Interpersonal interactions Psychological well-being

12. October 1512 Criteria for inclusion of domains Cross cultural comparability Suitability for self-report Parsimonious Validity across various methodological modes

13. October 1513 WG short set of questions for censuses: Because of a Health problem: 1)Do you have difficulty seeing even if wearing glasses? 2)Do you have difficulty hearing even if using a hearing aid? 3)Do you have difficulty walking or climbing stairs? 4)Do you have difficulty remembering or concentrating? 5)Do you have difficulty with (self-care such as) washing all over or dressing? 6)Using your usual (customary) language, do you have difficulty communicating (for example understanding or being understood by others)? Response categories: No - no difficulty; Yes - some difficulty; Yes - a lot of difficulty; Cannot do at all

14. October 1514 What do we end up with? Identify persons with similar types and degree of limitations in basic actions regardless of nationality or culture Represent the majority (but not all) persons with limitations in basic actions in any one nation Represent commonly occurring limitations in domains that can be captured in the Census context

15. October 1515 Intended use of data Compare levels of participation in employment, education, or family/social life for those with disability versus those without disability to see if persons with disability have achieved social inclusion Monitor effectiveness of programs / policies to promote full participation can be monitored Monitor prevalence trends for persons with limitations in specific basic activity domains

16. October 1516 Limitations One set of measures will not satisfy the multiple needs for disability data Excluded populations: Very young children Institutionalized population Homeless Floating populations It is not our purpose to: identify every person with a disability within every community replicate a population evaluated across a wider range of domains that would be possible with other forms of data collection

17. October 1517 An Example: Disability prevalence in Zambian: Data collected in a national household survey, 2006

18. October 1518 The Disablement Process ca.1980 Disease orImpairment(s) Disability(ies) Handicap(s) disorder Body level Personal level Societal level

19. October 1519 Measuring Disability: 1 Measurement based on impairments: the ”What’s wrong with you?” approach. Questions used to identify persons with disabilities: Zambia Census 1990 1. Are you disabled in any way? Yes/No 2. What is your disability? Blind Yes/No Deaf/dumb Yes/No Crippled Yes/No Mentally retarded Yes/No Disability prevalence = 0.9%

20. October 1520 Disability prevalence

21. October 1521 Global disability prevalence rates* High-income countriesLow-income countries Year% % Canada199114.7Kenya19890.7 Germany19928.4Namibia19913.1 Italy19945.0Nigeria19910.5 Netherlands198611.6Senegal19881.1 Norway199517.8South Africa19800.5 Sweden198812.1Zambia19900.9 Spain198615.0Kenya19890.7 UK199112.2Zimbabwe19971.9 USA199415.0Malawi19832.9 * Sources and methodologies are country specific

22. October 1522 Measuring Disability: 2 Zambia Census 2000 “…disability refers to a person who is limited in the kind or amount of activities that he or she can do because of on-going difficulties due to long term physical, mental or health problems.”

23. October 1523 Measuring Disability: 2 Questions used to identify persons with disabilities: Zambia Census 2000 1.Are you disabled in any way? Yes/No 2.What is your disability? Blind Yes/No Partially sightedYes/No Deaf/dumbYes/No Hard of hearingYes/No Mentally ill Yes/No Ex-Mental Yes/No Mentally retardedYes/No Physically handicapped Yes/No Disability prevalence = 2.7%

24. October 1524 Health Condition (disorder/disease) Body Function & Structure (Impairment) Activities (Limitation) Participation (Restriction) Environmental Factors Personal Factors Source: World Health Organization, 2001 The ICF Model - 2001

25. October 1525 Measuring Disability: 3 Because of a Health problem: 1)Do you have difficulty seeing even if wearing glasses? 2)Do you have difficulty hearing even if using a hearing aid? 3)Do you have difficulty walking or climbing stairs? 4)Do you have difficulty remembering or concentrating? 5)Do you have difficulty with (self-care such as) washing all over or dressing? 6)Using your usual (customary) language, do you have difficulty communicating (for example understanding or being understood by others)? Response categories: No - no difficulty; Yes - some difficulty; Yes - a lot of difficulty; Cannot do at all

26. October 1526 Measuring Disability: 3 The survey of Living Conditions among People with Disabilities in Zambia (2006) used the short set of 6 WG questions. Response categories: No difficulty, Some difficulty, A lot of difficulty, Unable to do it At least two of six Domains have at least some difficulty prevalence 13.4%

27. October 1527 Sample prevalence (%) by domain and degree of difficulty Core Domain Some difficulty A lot of difficulty Unable To do it Vision4.72.60.5 Hearing3.72.30.5 Mobility5.13.80.8 Remembering2.01.50.3 Self-Care2.01.30.4 Communicating2.11.40.5 At least:

28. October 1528 Overall Sample prevalence (%) Person with disability has:N% at least 1 Domain is ‘some difficulty’405314.5 at least 2 Domains are ‘some difficulty’309011.0 at least 1 Domain is ‘a lot of difficulty’23688.5 at least 1 Domain is ‘unable to do it’6732.4 more than 1 Domain is ‘some difficulty’17186.1

29. October 1529 Work on Extended Measures The WG is developing an extended set of questions that: goes into greater depth on the same 6 domains covered by the short set of questions, and includes additional domains of functioning such as learning, affect, pain and fatigue, includes questions about age at onset and impact of the difficulty, is currently being cognitively tested in preparation for subsequent field testing.

30. October 1530

31. October 1531 Basic activity domains Question topic Mobility Short set Do you have difficulty walking or climbing steps? Do you have difficulty moving around inside your home? Functioning without assistance 1.Do you have difficulty walking 100 (meters/yards) on level ground, that would be about the length of one (1) football field or one (1) city block? 2.Do you have difficulty walking half a km/ a third of a mile on level ground, that would be the length of five (5) football fields or five (5) city blocks? 3.Do you have difficulty walking up or down 12 steps? Probe How much difficulty would you have going up or down those steps without using a handrail? Use of AD/Micro- Environment 1. Do you use any equipment or receive help for getting around? 2. Do you use any of the following? Cane or walking stick? Walker? Zimmer frame? Crutches? Wheelchair? Prothesis(es)? Someone’s assistance? Other? Functioning with Assistance 1.Do you have difficulty walking 100 (meters/yards) on level ground, that would be about the length of one (1) football field or one (1) city block, when using your aid? 2.Do you have difficulty walking half a km/ a third of a mile on level ground, that would be the length of 5 football fields or 5 city blocks, when using your aid? 3.Do you have difficulty walking up or down 12 steps, even when using your aid?

32. October 1532 Mobility Severity Difficulty walking 100 meters on level ground NoneA littleA lotTotal Difficulty walking half a km on level ground None4993304996 A little4263607793 A lot34201159394 Cannot do it 3132642 Total54565771926225

33. October 1533 Basic activity domains Question topic Anxiety Short set How often do you feel worried, nervous or anxious? Daily, Weekly, Monthly, A few times a year, Never Use of AD/Micro- Environment Do you take medication for these feelings? Functioning: Extended questions 1.Thinking about the last time you felt worried, nervous or anxious, how would you describe the level of these feelings? A little, A lot, Somewhere in between a little and a lot 2.Would you say this was closer to a little, closer to a lot, or exactly in the middle? Probe: Please tell me which of the following statements, if any, describe your feelings. 1.My feelings are caused by the type and amount of work I do. 2.Sometimes the feelings can be so intense that my chest hurts and I have trouble breathing. 3.These are positive feelings that help me to accomplish goals and be productive. 4.The feelings sometimes interfere with my life, and I wish that I did not have them. 5.If I had more money or a better job, I would not have these feelings. 6.Everybody has these feelings; they are a part of life and are normal. 7.I have been told by a medical professional that I have anxiety.

34. October 1534 Anxiety Severity How often do you feel worried, nervous or anxious? A few times a yearMonthlyWeeklyDailyTotal Thinking about the last time you felt worried, nervous or anxious, how would you describe the level of these feelings? A little1087423328214205 2 In between 179126161104570 A lot16386122259630 Total5771429635611577

35. October 1535 Basic activity domains Question topic Pain Short set Functioning: Extended questions Do you have frequent pain? In the past 3 months, how often did you have pain? Never, Some days, Most days, Every day? Thinking about the last time you had pain, how long did the pain last? Some of the day, Most of the day, All of the day? Thinking about the last time you had pain, how much pain did you have? A little, A lot, Somewhere in between a little and a lot? Would you say the amount of pain was closer to a little, closer to a lot, or exactly in the middle? Probe: Please tell me which of the following statements, if any, describe your pain. 1.It is constantly present. 2.Sometimes I’m in a lot of pain and sometimes it’s not so bad. 3.Sometimes it is unbearable and excruciating. 4.When I get my mind on other things, I am not aware of the pain. 5.Medication can take my pain away completely. 6.My pain is because of work. 7.My pain is because of exercise.

36. October 1536 Pain Severity In the past 3 months, how often did you have pain? Never Some days Most days Every dayTotal Thinking about the last time you had pain, how long did the pain last? Some of the day 2815451461261845 Most of the day 5237181115538 All of the day 6272154187619 Total3920544814283002

37. October 1537 Additional domain specific Extended questions Age at onset How old were you when the difficulty walking or climbing began? Impact How much does your difficulty walking or climbing limit your ability to carry out daily activities? 1.Working to support you or your family? 2.Working outside the home to earn an income? 3.Going to school or achieving your education goals? 4.Participating in leisure or social activities? 5.Getting out with friends or family? 6.Doing household chores such as cooking and cleaning? 7.Using transportation to get to places you want to go? 8.Participating in religious activities? 9.Participating in community gatherings?

38. October 1538 Meeting Products & Information Executive summary of last eight WG meetings posted on the Washington Group website along with presentations & papers from the meetings: http://www.cdc.gov/nchs/citygroup.htm Publication of key papers in a special issue of Research in Social Science and Disability