the unemployment rate. I show that a simple frictionless business cycle model with heterogeneity and a simple form of on … employment growth. Worker flows are related to both employment growth and the unemployment rate, and quits and hires are …-the-job search, and quits beget hires to replace quitters. High unemployment crowds out quits, shortens the hiring chain, reduces the …

, this allows the model to generate fluctuations of unemployment, vacancies, and labor productivity whose magnitudes are …