Inequality in Survival

Abstract

Although inequality in survival is highly correlated with life expectancy, the authors believe that this form of health inequality should be better understood and that inequality in survival could be another useful summary measure of population health. It is also a motivation for assigning priority to the worse-off in priority-setting. Inequality in survival has previously been assessed by standard economic measures of income inequality, such as the Gini coefficient and Atkinson’s index. This chapter characterizes a new measure of inequality that is motivated by the geometry of survival curves rather than the distribution of income. The rectangularity index (r-index) is the fraction of total life expectancy contributed by individuals with above- average life expectancy, where 0 represents perfect equality (i.e., a rectangular survival curve where everyone dies at the same age). Analogously to questions asked in the income literature, the authors sought to determine whether global inequality in survival was increasing or decreasing. Using life tables from the United Nations Population Division, the authors found that inequality in life expectancy between countries and interindividual inequality in survival within most countries were decreasing. However, some countries still experienced high inequality and others even had periods with rising inequality. Overall, substantial reduction in inequality in survival was found within and between countries. The relevance for priority-setting is that while policies to reduce premature mortality will both improve life expectancy and reduce inequality in survival, there remains potential for additional inequality reduction.