Healthier, Wealthier and Wiser: A Demonstration of Compositional Changes in Aging Cohorts Due to Selective Mortality

Anna Zajacova, University of Wyoming

The gradual changes in cohort composition that occur as a result of selective mortality are of interest to all aging research. We present the first illustration of changes in the distribution of key cohort characteristics that arise purely due to selective mortality, using data from the Health and Retirement Survey (N=14,466). We calculate sample statistics for the surviving cohort at each wave, repeatedly using only baseline information so that there are no changes at the individual level -- only the set of surviving respondents at each wave changes. We find substantial changes in the distribution of examined characteristics across nine survey waves. For instance, the median wealth increases from about $90,000 to $130,000. The mortality selection process changes the composition of older cohorts considerably, such that researchers focusing on the oldest old need to be aware of the highly select groups they are observing, and interpret their conclusions accordingly.