Longevity and Lifetime Labor Input: Data and Implications,” 2006. Unpublished manuscript

Recent growth theories have utilized the Ben-Porath (1967) mechanism according to which prolonging the period in which individuals may receive returns on their investment spurs investment in human capital and cause growth. An important, though sometime implicit implication of these models is that total labor input over the lifetime increases as longevity does. We propose a thought experiment to empir-ically evaluate the relevancy of this mechanism to the transition from “stagnation” to “growth ” of the nowadays developed economies. Specifically, we estimate the ex-pected total working hours over the lifetime of nine consecutive cohorts of American men born between 1840 and 1920. Our results show that despite a gain of almost 9 years in the expectations of life at age 20, the expected total working hours over the lifetime have declined from more than 117,000 hours to less than 90,000 between the oldest and the youngest cohorts. We conclude that the Ben-Porath mechanism have had a lesser effect than previously thought on the accumulation of human capital during the growth process