Jan 1, 1992
Published in: Measuring Functioning and Well-Being: The Medical Outcomes Study Approach / edited by Anita L. Stewart and John E. Ware, Jr., (Durham, N.C.: Duke University Press, 1992), Chapter 6, p. 86-101
Posted on RAND.org on January 01, 1992
Many measures of physical functioning combine questions about physical and other activities into one measure, labeled "functional status" or "activities of daily living." However, whether an individual can perform such activities is determined by factors other than physical health, and social and role activities are treated separately in the MOS. In determining the appropriate content for measures of physical functioning, the researchers address eight issues in this chapter: (1) identification of appropriate content, which limits physical activities to those that are most likely to be the same for all people regardless of their life situation; (2) avoiding coarseness, which required developing more scale levels and using a scaling method that avoids aggregation at a particular scale level; (3) the range of physical activities, which was extended into more-strenuous activities, such as running and walking, to improve precision; (4) whether the extent of difficulty or the need for help should be assessed, to identify limitations; (5) whether the degree of difficulty and the need for help should be assessed separately; (6) aggregating categories of physical functioning--self-care, mobility, and other physical activities--and whether separate scales should be constructed for each category; (7) people's values for different levels of functioning, which would be independent of a measure of physical functioning; and (8) a method of scoring the measures that would be simpler than the Guttman scaling used earlier. This chapter describes the two pilot studies that were conducted to address these issues; the construction and evaluation of the measures; characteristics of the measures, including tables of descriptive statistics; and resolution of issues and further directions--for example, the coarseness of most existing scales was improved by developing a physical functioning scale that potentially has 21 scale levels, all of which were represented, and the pilot studies indicated that it is unnecessary to ask separately about the need for help with basic activities as long as one asks about the extent of limitations in performing these activities.