Projecting Social Security earnings: past is prologue.

Accurate projections of lifetime earnings are useful in projecting Social Security benefits, trust fund balances, and economic resources of the elderly and the effects of changes in Social Security policy. This article projects lifetime Social Security earnings until retirement using data from the Survey of Income and Program Participation (SIPP) matched to Social Security records of annual earnings from 1951 through 1993. We first develop, estimate, and test gender-specific multiple regression models of 10-year earnings intervals using the matched 1984 SIPP panel. We find strong relationships predicting the mean indexed monthly earnings level in the 10-year period of 1984-93. We then use the models to project (unobserved) Social Security earnings from 1994 through retirement for persons born between 1931 and 1955. By adding projected earnings to observed annual earnings to date, we forecast lifetime Social Security earnings for persons retiring early in the 21st century.