The vanishing procyclicality of labor productivity

We document two changes in post-war US macroeconomic dynamics: the procyclicality of labour productivity vanished, and the relative volatility of employment rose. We propose an explanation for these changes that is based on reduced hiring frictions due to improvements in information about the quality of job matches and the resulting decline in turnover. We develop a simple model with hiring frictions and variable effort to illustrate the mechanisms underlying our explanation. We show that our model qualitatively and quantitatively matches the observed changes in business cycle dynamics