Longevity and Lifetime Labour Input: Data and Implications

The Ben-Porath (1967) mechanism suggests that prolonging the period during which individuals may receive returns on their investment spurs investment in human capital and causes growth. An important, albeit implicit implication of this mechanism is that the total labour input over a lifetime must increase as longevity does. Otherwise, the incentive to invest in education would not increase. We propose an empirical evaluation of the relevance of this mechanism to the transition from 'stagnation' to 'growth' in today?s developed economies. Specifically, we estimate the expected total lifetime working hours of consecutive cohorts of American men born between 1840 and 1970. Our results show that despite a gain of more than 15 years in life expectancy at the age 5, the expected total lifetime working hours have declined by more than 20 percent between the oldest and youngest cohorts. Furthermore, the similarity in the trends and the magnitudes of the determinants of total lifetime labour input between the US and many European countries suggest that our result is not confined to the US experience; rather, it is a robust feature of the process of development. We conclude that the Ben-Porath mechanism has had no effect on the accumulation of human capital during the growth process of the nineteenth and twentieth centuries.