A distributional approach to measuring lifespan stratification

The study of the mortality differences between groups has traditionally focused on metrics that describe average levels of mortality, for example life expectancy and standardized mortality rates. Additional insights can be gained by using statistical distance metrics to examine differences in lifespan distributions between groups. Here, we use a distance metric, the non-overlap index, to capture the sociological concept of stratification, which emphasizes the emergence of unique, hierarchically layered social strata. We show an application using Finnish registration data that cover the entire population over the period from 1996 to 2017. The results indicate that lifespan stratification and life-expectancy differences between income groups both increased substantially from 1996 to 2008; subsequently, life-expectancy differences declined, whereas stratification stagnated for men and increased for women. We conclude that the non-overlap index uncovers a unique domain of inequalities in mortality and helps to capture important between-group differences that conventional approaches miss.

Automated summary

Traditionally, the study of mortality differences between groups has focused on average levels of mortality, such as life expectancy and standardized mortality rates. However, using statistical distance metrics to examine differences in lifespan distributions between groups can provide additional insights. In this study, the non-overlap index is used to capture sociological stratification in lifespan. The findings based on Finnish registration data from 1996 to 2017 show that lifespan stratification and life-expectancy differences between income groups increased significantly from 1996 to 2008. The life-expectancy differences declined thereafter, while stratification stagnated for men and increased for women. The non-overlap index uncovers an unique domain of inequalities in mortality and helps capture important between-group differences that conventional approaches miss.