Saturday, 3 October 2009

Downturns and life expectancy

I don't buy it. GNXP points to a study claiming that the Great Depression increased life expectancy.
Recent events highlight the importance of examining the impact of economic downturns on population health. The Great Depression of the 1930s was the most important economic downturn in the U.S. in the twentieth century. We used historical life expectancy and mortality data to examine associations of economic growth with population health for the period 1920-1940. We conducted descriptive analyses of trends and examined associations between annual changes in health indicators and annual changes in economic activity using correlations and regression models. Population health did not decline and indeed generally improved during the 4 years of the Great Depression, 1930-1933, with mortality decreasing for almost all ages, and life expectancy increasing by several years in males, females, whites, and nonwhites. For most age groups, mortality tended to peak during years of strong economic expansion (such as 1923, 1926, 1929, and 1936-). In contrast, the recessions of 1921, 1930-1933, and 1938 coincided with declines in mortality and gains in life expectancy. The only exception was suicide mortality which increased during the Great Depression, but accounted for less than 2% of deaths. Correlation and regression analyses confirmed a significant negative effect of economic expansions on health gains. The evolution of population health during the years 1920–1940 confirms the counterintuitive hypothesis that, as in other historical periods and market economies, population health tends to evolve better during recessions than in expansions.
It sounds to me like what's going on is that the downturn makes folks poorer and consequently more willing to take on risk for little compensation. When the economy ticks up a bit, folks jump into those riskier jobs and mortality goes up. But it isn't the recovery that did it; rather, it's the effect of the prior increase in poverty affecting folks' willingness to accept risk.

At least that's my first cut explanation. It's at least consistent with the Viscusi and Aldy finding that the income elasticity of the value of a statistical life is about 0.5 to 0.6. Recall that Viscusi's numbers all come from revealed willingness to pay to accept risk: as folks get richer, they require higher compensation for a given risk. If the first study were right, elasticity would be negative. I don't buy it.