ABSTRACT
In the US and several other developed countries there is increasing evidence that disability declined during the 1980s - and possibly was stable or declining in the 1970s. Education is negatively associated with mortality levels and possibly with age specific disability levels. In any observational plan for assessing chronic disability, or other long term health changes, one must balance, against the resources consumed in data collection, the length of the inter-survey interval, and the temporal frequency and duration of the health state transitions that will be observed. Though age specific disability risks for individuals may decline it is not clear how such declines will ultimately be manifested at the general population level. The increase in longevity among the chronically disabled could be blended with declines in chronic disability incidence to reduce the overall level of population declines in the prevalence of chronic disability.
