Opportunities to Improve Survey Measures of Late-Life Disability: Part II - Workshop Summary. OPPORTUNITIES FOR NEW MEASURES OF LATE-LIFE DISABILITY


The first panel brought together researchers using disability data for both basic and policy studies and a representative of the Social Security Administration (SSA) for a discussion organized around four questions:

  • What are important new research and policy questions relating to late-life disability? Do they imply different data needs for policy makers than for researchers?
  • What are the shortcomings of current measures of ADL, IADL, and physical or mental limitations for addressing these questions?
  • For what questions and purposes are current measures the “right” concept, and what modifications would improve how well they measure the concept?
  • For what questions and purposes do we need new measures?

The panelist’s comments and subsequent discussion suggested the potential for common ground on how new measures and improvements to existing measures might meet the needs of both. From the researcher perspective, more emphasis was placed on better understanding the underlying processes that drive disability and disability trends and the implications for identifying persons at risk and predicting future trends. From the program perspective, more emphasis was placed on reliable, objective measures that predict program eligibility and participation.

Dr. Susan Allen and Dr. Robert Schoeni focused on the need to understand the causes of observed declines in old age disability in order to understand potential for effective interventions.

Dr. Allen noted that the causal pathways for disability are complex and different approaches may be needed to determine the role of socio-cultural and individual factors. We do not yet know the extent to which improvements in functioning may reflect healthier lifestyles among the older population, widespread changes at the societal level in how we perform the daily activities assessed in measures of IADLs and ADLs, or changing attitudes toward exercise and general physical activity or expectations about aging by both older persons and their informal network of informal caregivers. She suggested that measuring such individual factors as social involvement and personality characteristics (e.g., introvert/extrovert); potential early markers of decline such as level of fatigue and changes in activities or activity level; and characteristics of the physical environment may help identify those at risk for decline and the importance of these factors in preventing or deferring decline.

Dr. Schoeni identified a better understanding of differentials in disability decline across sociodemographic groups, across time and across geography as a key issue for both research and policy. He suggested that the underpinnings for better understanding might include more focus on identifying the factors and stage of life associated with higher disability rates. Examples are measures of very early life characteristics and events, for example birth weight, that may predict later life disability risks. He also noted the need for capturing the impacts of nonhealth factors--social, economic, and community policies--on health and disability. Focusing on ADLs and IADLs without sufficient information about accommodations used (including accommodations not conventionally thought of as assistive technology), and relevant aspects of the physical environment, household, and community may mask the effectiveness of policies that are “paying off.” Such factors may affect both whether an individual has disability and whether the individual reports disability.

Dr. Schoeni also raised two issues that were a common theme among the panelists and in subsequent discussion: Measuring time costs of disability and the role of mental health and individual attitudes would provide insight into disability and its impact not supported by current measures. He gave the example of “daily reconstruction” using time diaries and eliciting respondent feelings about the time required to perform various activities being considered for the Panel Study of Income Dynamics (PSID).

Dr. Howard Iams noted that from SSA’s perspective, a key issue is understanding the relationship between disability and “wellbeing,” specifically factors that improve understanding of the timing of retirement and identify ability to work past traditional retirement ages as life expectancy continues to increase. From that perspective, ADLs and IADLs are less useful than actual measures of physical functioning or ability, such as “Nagi” items (e.g., walking short distances, climbing stairs, and lifting and carrying something weighing ten pounds) that determine degree of difficulty with components of more complex physical activities. Iams noted that better measurement of physical abilities, including more attention to measures that allow scaling of difficulty level, would provide an empirical underpinning for considering the potential for linking full benefits to life expectancy, as increasing longevity pushes Social Security costs upward.

A particular concern from the program perspective is that measures be operationally feasible, preferably in administrative data, and consistent across surveys and time. Specific measurement issues raised were the reliability of self-reports versus objective measures and the conditional format of disability measures on many surveys so that functioning is not assessed for the full survey sample. Iams noted the SSA’s disappointing experience with efforts to use existing self-report survey measures, including ADL difficulty or a condition that limits work, to predict receipt of disability benefits. Like Schoeni, he advocated more and better measures of mental health, which is the basis of eligibility for 1/3 of disabled beneficiaries, and of time required to perform activities.

Dr. Lisa Iezzoni said that better information is needed on sensory impairments, which may result in disability and in reduced participation in all areas of life. Simple but effective treatments or accommodations that may delay or prevent disability resulting from such impairments (e.g., hearing aids) are not covered by Medicare.

She noted that shortcoming of existing ADL/IADL measures. For example, just as IADL questions may fail generic changes such as the advent of microwave ovens that make meal preparation less physically demanding, ADL questions fail to capture accommodative practices, such as wearing only elastic waist pants, that may allow independent dressing but are not commonly thought of as explicitly disability-related. More attention might be focused on how rather than whether activities are accomplished. This focus could also apply to improvements in measures of assistive device use, since a focus on whether particular devices are used for particular applications fails to capture the full array of devices and the multiple contexts in which they are used. Iezzoni also noted that the cross-sectional focus of most data collections (e.g., now, in the last week) fails to capture the waxing and waning of abilities that characterize many disability-related conditions and diseases. Finally, Iezzoni suggested improving the information collected on household structure, including who lives in the household and is available to assist with activities as a matter of course, which may affect disability reporting.

A number of additional observations and elaborations were made by meeting participants and panelists:

  • A better understanding is needed of mental health and impairments beyond current memory and cognitive functioning measures and how they interact with ADL measures.
  • Better ways are needed to control for endogeneity that limits the ability to demonstrate whether such medical inputs as restorative procedures and advances in medications are effective in reducing or delaying functional decline.
  • Dependence on ADLs, in particular, as a disability measure may be too narrow to capture the broad range of disability across the age spectrum; better and more broadly applicable measures might focus on physical functioning necessary to perform activities rather than on the activities themselves.
  • Distributional issues are crucial to consider in disability measurement: ethnic, racial, and socio-economic factors may affect biological aging and access to services and technology; geographic disparities in public benefits, infrastructure, and accommodative built environment also affect disability rates.
  • ADLs, while perhaps limited as a measure of population disability, have value in terms of measuring long-term care use and needs and are the foundation for eligibility for both public and private insurance benefits for older persons.
  • The difficulty in separating need from individual preferences pose a methodological problem for measuring time costs of disability.

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