MODELING AND FORECASTING UNITED-STATES SEX DIFFERENTIALS IN MORTALITY

This paper examines forecasted differentials in age-sex-specific mortality in the United States, 1990-2065. A non-linear model, m(x,t) = exp(a(x) + b(x)k(t) + e(x,t)), is fitted for each sex to a matrix of age-specific US death rates, 1933-1988, using SVD to derive a single time-varying index of mortality, k(t). Box-Jenkins techniques are used to estimate and forecast k(t). These forecasts are used to generate age-specific mortality rates and life expectancies to 2065. Independent forecasts of male and female e0's are 82.0 and 90.4, respectively, for 2065, a difference of 8.4 years. These forecasts are substantially higher with narrower confidence intervals than those prepared regularly by the Actuary of the Social Security Administration [Wade (1989)]. These k(t) generated forecasts of e0 appear more plausible than direct forecasts of e0 Life expectancies derived from jointly estimated and forecasted k(t) are competitive with the independent sex forecasts, but have some problems. Joint forecasts of k(t) are juxtaposed to co-integration speculatively as a direction for future research into linkages between male and female mortality.