Aggregate and sectoral comovement are central features of business cycles, so the ability to generate comovement is a natural litmus test for macroeconomic models. But it is a test that most models fail. We propose a unified model that generates aggregate and sectoral comovement in response to contemporaneous and news shocks about fundamentals. The fundamentals that we consider are aggregate and sectoral total factor productivity shocks as well as investment-specific technical change. The model has three key elements: variable capital utilization, adjustment costs to investment, and preferences that allow us to parameterize the strength of short-run wealth effects on the labor supply.

Job polarization refers to the shrinking share of employment in middle-skill, routine occupations experienced over the past 35 years. Jobless recoveries refers to the slow rebound in aggregate employment following recent recessions despite recoveries in aggregate output. We show how these two phenomena are related. First, essentially all employment loss in routine occupations occurs in economic downturns. Second, jobless recoveries in the aggregate can be accounted for by jobless recoveries in the routine occupations that are disappearing.

Over the business cycle young workers experience much greater volatility of hours worked than prime-aged workers. This can arise from age differences in labor supply or labor demand characteristics. To distinguish between these, we document that, for young workers, both the cyclical volatilities of hours and wages are greater than those of the prime-aged. We argue that a general class of models featuring only age-specific labor supply differences cannot reconcile these facts. We then show that a simple model featuring labor demand differences can.