Smooth transition trends and labor force participation rates in the United States

This paper employs smooth transition trend models to investigate the long-run time series behavior of quarterly US labor force participation rates. In particular, we examine whether long-run growth in labor force participation rates can be modeled by smooth transitions between states rather than as abrupt mean level changes or as a stochastic trend. Smooth transitions permit for non-instantaneous adjustment of individual workers to changes associated with economic events or general labor market conditions. We employ unit root testing procedures with alternatives characterized by stationary fluctuations around one or two smooth transitions in linear trend. We examine labor force participation rates by gender- and age-specific groups. The results indicate that all female and most male participation series are better characterized as stationary processes that undergo transitional deterministics.