NBER Publications by Ryan D. Edwards

Entropy, or the gradual decline through age in the survivorship function, reflects the considerable amount of variance in length of life found in any human population. Part is due to the well-known variation in life expectancy between groups: large differences according to race, sex, socioeconomic status, or other covariates. But within-group variance is very large even in narrowly defined groups, and it varies strongly and inversely with the group average length of life. We show that variance in length of life is inversely related to the Gompertz slope of log mortality through age, and we reveal its relationship to variance in a multiplicative frailty index. Our findings bear a variety of implications for modeling and forecasting mortality. In particular, we examine how the assumption of ...

A considerable amount of uncertainty surrounds life expectancy at birth, the average length of life. The standard deviation in adult life spans is about 15 years in the U.S., and theory and evidence suggest it is costly. In this paper, I calibrate a standard intertemporal model to show that one less year in standard deviation is worth about half a mean life year. Differences in the standard deviation amplify measured differences in life expectancy between the U.S. and other industrialized countries, and accounting for historical gains against the standard deviation raises the total value of mortality declines during the last century by about 25 percent.