Dissertation Title： "Disability and Physical Functioning in the Elderly"Self-reported disability among the elderly population declined over the past 25 years. Since the share of elderly living with chronic disease increased and improvements in technologies and environments may have facilitated independence over this timeframe, it is likely that improved medical care and increased use of technologies and environments may explain some of the disability decline. The goals of this dissertation are to evaluate the relative importance of technologies and environments on disability survey responses, to investigate whether a new survey technique, anchoring vignettes, identifies systematic differences in self-reported disability, and to evaluate the impact of improved medical care on disability.
The first two papers are based on a new survey of 441 community-dwelling elderly conducted in the greater Boston area. The first chapter examines whether use of various technologies and environmental factors were important determinants of self-reported disability, conditional on objective measures of functioning. This study finds that a majority of respondents who used walking aids did not report disability walking around inside. In addition, increased use of van service, senior housing and ramps may explain up to 19% of the decline in disability grocery shopping between 1982 and 1999.
The second chapter explores whether anchoring vignettes, a new survey technique, identifies systematic differences in thresholds for reporting disability. We hypothesized that respondents who used various technologies and environments may have a higher threshold, i.e. lower propensity, to report disability compared to non-users. In models for walking around inside, we found that respondents using mobility assistance actually had lower thresholds for reporting disability and that random variation across respondents was an important determinant of survey responses.
In the third chapter, we use data from the National Long Term Care Survey, including Medicare-linked files, to evaluate whether improved treatment for acute myocardial infarction led to lowered disability and death among the elderly population over time. We find that increased use of invasive procedures was associated with improved survival and lower disability among survivors, and that increased use of beta-blockers were associated with improved survival. These findings suggest that improved medical care treatment led to greater survival and lower disability.