Selection into Poverty, Selection into Death: A Multi-Stage Extension of Mortality Selection to Explain a Surprising Result about Mortality Deceleration and Acquired Disadvantage

Elizabeth Wrigley-Field, University of Wisconsin at Madison
Felix Elwert, University of Wisconsin at Madison

The dominant explanation for mortality deceleration is mortality selection: aggregate mortality’s rise slows at old ages as the frail die. Using Medicare data to follow 28 million Americans for nine years, we incorporate key dimensions of social and biological heterogeneity to reevaluate this explanation. Our results create an apparent puzzle. Examining race and sex gives the expected pattern: higher-mortality African-Americans and men decelerate earlier and more steeply -- with black men even evincing mortality decline. For health and poverty, however, the pattern reverses: it is the non-sick and, especially, non-poor whose mortality decelerates substantially earlier. Drawing on sociological literature suggesting mutual causation between poverty and ill health, we offer a Multi-Stage Mortality Selection model in which the non-poor elderly may face the greatest selective pressure, despite low mortality. We show that acquired traits add considerable complexity to evaluating mortality selection, but generating predictions remains possible.