Individual mobility, population growth and labor force participation.

Trends in labor force participation rates and the age of retirement are shown to be important of upward mobility. Reductions in age specific participation rates increase the speed of movement through the employment hierarchy. In conjunction with economic development, the falling labor force participation of older men acts to offset the adverse effects of slowing population growth on promotional prospects. These conclusions are reached by extending a model of employment status developed by Keyfitz to limit employment competition to only those actually in labor force.