Measuring Disability in Canadian Questionnaires: A First Look Sally Kader Health Statistics Division Statistics Canada

Objectives To assess the differences in estimates of disability from filter (screening) questions in different surveys To examine the association between disability as measured by the filter questions and other measures of health or functional limitations

Surveys with disability questions Census Health Surveys: Canadian Community Health Survey (CCHS), National Population Health Survey (NPHS) Post-Censal Surveys: Participation and Activity Limitations Survey (PALS), Aboriginal Peoples Survey (APS) Labour Surveys: Labour Force Survey (LFS), Survey of Labour and Income Dynamics (SLID), Workplace and Employee Survey Other Surveys: National Longitudinal Survey of Children and Youth, General Social Survey (GSS)

Sources of data Health –2000 CCHS –1998 NPHS –1996 NPHS Non-health –2001 Census –1999 SLID –2000 GSS

Filter questions: Census prior to 2001 Is this person limited in the kind or amount of activity he/she can do because of a long-term physical condition, or mental condition or a health problem: –...at home? –…at school or at work? –…in other activities, for example, in transportation to and from work, or in leisure time activities? Does this person have any long-term disabilities or handicaps? Responses –No, not limited –Yes, limited

Do you have any difficulty hearing, seeing, communicating, walking, climbing stairs, bending, learning or doing any similar activities? Does a physical condition or mental condition or health problem reduce the amount or the kind of activity you can do –… at home? –…at work or at school? –…in other activities, for example, transportation or leisure? Responses –Yes, often –Yes, sometimes –No, never Filter questions: Census 2001

Prevalence of population identified as “disabled”, by survey

Self-perceived health (SPH) –NPHS and CCHS only –A global evaluation of one’s health on a 5-point scale. –Response categories: “excellent”, “very good”, “good”, “fair” or “poor.” –Indicator scored as 1 if response is “fair” or “poor.” Selected health status measures

Health Utilities Index (HUI) –NPHS and CCHS only –A set of 30 questions covering 8 components: vision, hearing, speech, mobility, dexterity, pain, emotion, cognition. –Each component has 2 levels: none/mild and moderate/severe. –Indicator scored as 1 if response indicates moderate/severe impairment in any component.

Activities of daily living (ADL and IADL) –NPHS and CCHS only –A set of 6 questions about needing help in preparing meals, shopping for groceries or other necessities, housework, heavy chores, personal care, moving inside house. –Response categories: Yes/No. –Indicator scored as 1 if “Yes” response to any of the questions. Selected health status measures

Prevalence under disability filter questions and selected health status measures

Defining disagreement between filter questions and selected health status measures False negatives –No to all the filter questions –A positive score on another health measure False positives –Yes to at least one of the filter questions –A zero score on health measure under consideration

Adjusted prevalence –NPHS and CCHS only –Exclude false positives –Estimate prevalence based on filter questions only Method used to adjust prevalence estimates of disability

Percentage of disagreement between filter questions and other selected health status measures Data Source: NPHS 1996

Data Source: NPHS 1998 Percentage of disagreement between filter questions and other selected health status measures

Data Source: CCHS 2000 Percentage of disagreement between filter questions and other selected health status measures

Summary As expected, the redesigned filter questions yield higher estimates of the prevalence of disability than do former filter questions or other measures of health or functional limitation. CCHS estimates of prevalence of disability, based on the redesigned filter questions, are higher than those obtained from other surveys

CCHS: Higher rates Possible explanations: –New questions –Question placement –Proxy rates –Larger percentage of respondents choosing “sometimes” –Health context

Limitations Proxy reporting rates vary Method of questionnaire administration (in- person, telephone or self-completed)

Next steps Evaluate the possible effects of: –Health context of survey –Proxy reporting –Method of questionnaire administration (in- person, telephone or self-completed) –Question placement in survey –Short time span