over time in a population but it ignores the return to good health from poor health which is an important aspect of any individual's pattern of change in health. Recent studies of health change in the older ages have employed a dynamic perspective to examine health change in both directions- getting sick and getting well ( Crimmins and Saito, 1990; Rogers, et al., 1990). These studies have demonstrated the importance of rehabilitation to wellness in affecting the overall level of health in a population. Emphasis on rehabilitation or the return of lost functioning which can accompany chronic disease is also important in determining the societal level of good health.
The method applied to determine the adjustment for the series of limitation of activity was to regress the annual proportion reporting limitation of activity for each age group on year, year squared, a dummy variable for 1977, and a dummy variable for the time period from 1982 through 1988. The adjustment was made using the coefficients for the 1977 dummy and the 1982 through 1988 dummy.
For each series the equation resulted in an R2 greater than .90. Adjustments were made when the probability level of the coefficient was. I or smaller.
The procedure for adjusting restricted activity days was similar except that no indicator for 1977 was included in the regression.