Dr. Jennifer Madans provided an overview of national and international efforts to create brief measures of disability. She began by noting that measures of ADLs and IADLs, while widely used, do not adequately reflect the full spectrum of the concept of disability. She then went on to provide a summary of the recent activities of the Washington Group, the inter-departmental workgroup tasked to review the disability questions on the American Community Survey (ACS), and a task force on health measurement formed by UNECE, WHO, and Eurostat.
Under the aegis of the United Nationals Statistical Commission, City Groups are formed to address important problems in statistical methods. The Groups are composed of international experts, primarily from the national statistical authorities. The Washington Group, named after the location of its first meeting, was convened to promote the co-ordination of international cooperation in the area of health statistics by focusing on disability measures suitable for censuses and national surveys, which will provide basic necessary information on disability throughout the world.
The groups current objectives are to develop and test 2-3 sets of general questions for international use in censuses; to understand the limited choices associated with developing census questions; and to understand the product that results from census questions. A fourth objective, is to recommend an extended set of items (including functioning, participation, and the environment) that can be added to collect information on disability on population surveys of all kinds. The group will also address methodological issues associated with disability measurement, including measures for special populations (e.g., children, those living in shared residential care settings).
The Washington Group uses the International Classification of Functioning, Disability and Health (ICF) as a conceptual framework. The ICF depicts disability as the interaction between individual characteristics and the environment. The components of the model include body functions and structures, activities, participation, health conditions, environmental factors, and personal factors. The ICF provides the conceptual building blocks for users who wish to study different aspects of the disablement process, but it does not provide a way to measure the concepts. Thus the Washington Groups task is to operationalize the concepts for use in censuses around the world.
The group began by identifying three possible major purposes for measuring disability in a census: (1) to provide information around the provision of services; (2) to monitor the level of functioning in a population; and (3) to monitor equalization of opportunity. The characteristics of the measures to be developed will depend on the purpose chosen. For Censuses, equalization of opportunity was selected as the primary purpose of data collection. To meet this purpose, information is collected to identify those who would be at greater risk than the general population for limitations in activity or participation without accommodation. Questions would be designed to meet the criteria of cross-cultural comparability, suitability for self-report, parsimony, and validity across modes of data collection.
The Washington Group recommended that the Census questions should, at a minimum, cover three essential domains of functioning: walking, seeing, and cognitive functioning. Additional domains identified were hearing, upper body functioning and communication. In recommending response categories, the group recognized tradeoffs between the ease and comparability of yes/no outcomes versus the need for capturing degrees of difficulty with finer categories.
Washington Group Recommended Census Items
- Do you have difficulty seeing even if wearing glasses?
- Do you have difficulty hearing even if using a hearing aid?
- Do you have difficulty walking or climbing stairs?
- Do you have difficulty remembering or concentrating?
- Do you have difficulty with (self-care such as) washing all over or dressing?
- Because of a physical, mental, or emotional health condition, do you have difficulty communicating (for example, understanding others or others understanding you)? a) No -- no difficulty, b) Yes -- some difficulty, c) Yes -- a lot of difficulty, d) Cannot do at all
These measures are now being tested in a variety of countries. The Washington Group is facilitating the process by training country representatives in cognitive testing, translation, and other relevant areas, and by developing an analysis plan for pre-test results.
In the United States, the disability questions that were on the 2000 Census and that are now on the ACS are going through a process of review with results similar to that of the Washington Group. The workgroup also chose equalization of opportunity as the main purpose of the measures and decided to focus on four key domains: hearing, seeing, walking and cognition. They also included one item to capture severe disability affecting the need for long-term care. Recommended items (with yes/no response categories) appear below. The first two items are asked for all ages, items 3-5 are asked for respondents ages 5 and older, and item 6 for ages 17 and older. The items have undergone extensive cognitive testing and will be included in the ACS content test.
Recommended American Community Survey Items
- Is this person deaf or do they have serious difficulty hearing?
- Is this person blind or do they have serious difficulty seeing, even when wearing glasses?
- Because of a physical, mental, or emotional condition, does this person have serious difficulty concentrating, remembering, or making decisions?
- Does this person have serious difficulty walking or climbing stairs?
- Does this person have difficulty dressing or bathing?
- Because of a physical, mental, or emotional condition, does this person have difficulty doing errands alone such as visiting a doctors office or shopping?
Dr. Madans also briefly reviewed efforts by UNECE, WHO and Eurostat to develop a common instrument to measure health states. Their aim requires a multidimensional measurement approach, one which focuses on the capacity of the individual, and maximizes cross-population comparability. The collaborative effort is in the process of identifying a core and extended set of domains.
Dr. Madans concluded with a set of recommended next steps for measurement of late-life disability. She suggested that major surveys and censuses would benefit from less reliance on ADLs as the primary indicator of disability and more attention to measures of basic functioning, or precursors to ADL and IADL limitations. She recommends differentiating between capacity to perform and actual performance (with and without aids/assistance). In addition, she suggests reformulating the IADLs and expanding the range of participation domains measured and studies.