data collection. Participants included academic researchers and representatives of various federal and private-sector agencies with a policy interest in disability. The format of the workshop was informal to facilitate interaction among speakers, discussants, and observers.
The specific objectives of the workshop were fourfold: (1) assess and compare findings from various studies of disability trends in the elderly population; (2) consider potential sources of bias that may explain differences in trends from different surveys; (3) identify potential explanations of observed trends in disability; and (4) examine implications of data and methods for forecasting disability trends. This report is a summary of the workshop proceedings and discussions. The first section reviews the evidence presented at the workshop regarding emerging trends in disability. The second section outlines issues raised regarding forecasting trends in disability, including implications of recent trends for further research. A summary of findings is presented in the final section.
Survey data, from both cross-sectional and prospective panel studies, provide insight into trends in disability at older ages. There is no general agreement with respect to the conceptual definition of disability, and no standard for measuring disability in old age. Furthermore, disability can be considered a multidimensional construct, encompassing both cognitive and physical limitations.
Surveys of the population aged 65 and older generally focus on a person's ability to carry out activities essential to maintain independence. Such surveys usually include measures of an individual's ability to perform basic self-care activities, such as bathing, dressing, and feeding oneself. Such measures are generally referred to as activities of daily living or ADLs (Katz and Apkom, 1976). Measures that assess independence in activities requiring adaptation to the environment, such as shopping, preparing meals, and carrying out household chores, are generally called instrumental activities of daily living or IADLs (Lawton and Brody, 1969). Because ADLs and IADLs focus on the level of dependence in activities, rather than the underlying cause of that dependence, distinctions between physical and cognitive impairments cannot be drawn from such measures. Nevertheless, ADLs and IADLs are thought to be hierarchical, with ADL limitations representing more severe disability.