Beyond Differences in Means: Rising Mortality Stratification among Income Groups in Finland, 1996-2014

Jiaxin Shi , Max Planck Institute or Demographic Research
José Manuel Aburto, CPop, University of Southern Denmark
Pekka Martikainen, University of Helsinki
Lasse Tarkiainen, University of Helsinki
Alyson A. Van Raalte, Max Planck Institute for Demographic Research (MPIDR)

The study of the mortality differences in social groups has traditionally focused on factors such as life expectancy and mortality rates. These indices can give us insights into how social characteristics is linked with mortality. But more insights can be gained by examining differences in age-at-death distributions between social groups. Here we measure the degree of overlap in the age-at-death distributions – mortality stratification – to capture important between-group differences that conventional life expectancy comparisons miss. This stratification can reveal the extent to which the two groups experience unique mortality regimes and experience of social lives. However, mortality stratification, and its relationship with life expectancies, is not well studied. We focus on five income groups in Finland, conditional on surviving to 30 and based on the Finnish registry data. We find that both stratification and difference in life expectancies in these groups increased substantially from 1996 to 2005. In more recent years, the difference in life expectancies declined, whereas stratification stagnated. This could be explained by the increase in lifespan standard deviation among the lowest income group. Our decomposition analyses suggest that the most effective way to reduce mortality stratification is to reduce the low income group’s deaths in ages between 50 and 74. Because mortality stratification reflects differences in both life expectancy and age-at-death variability, it provides a useful summary measure of mortality differences between social groups.

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 Presented in Session 9. Mortality and Longevity