This course presents various matching models of unemployment. It uses them to study unemployment fluctuations, job rationing, unemployment gap, and labor market policies—minimum wage, payroll tax, public employment, and unemployment insurance.
This paper shows that when unemployment is inefficient, optimal public expenditure deviates from the Samuelson rule to reduce the unemployment gap. Optimal stimulus spending depends on the unemployment gap, unemployment multiplier, and an elasticity of substitution.
This paper develops a New Keynesian model in which the government multiplier doubles when the unemployment rate rises from 5% to 8%. The multiplier is so countercyclical because in bad times, on the labor market, job rationing dwarfs matching frictions.