Twenty years have passed since Freeman and Medoff's What Do Unions Do? This essay assesses their analysis of how unions in the U.S. private sector affect economic performance - productivity, profitability, investment, and growth. Freeman and Medoff are clearly correct that union productivity...

We present a production-based model in which agents have heterogeneous risk aversion and heterogeneous discount rates. When the less risk-averse agent is more impatient, the two types of agents can coexist for a long time. The heterogeneity in risk aversion and discount rate induces the wealth...