Do Matching Frictions Explain Unemployment? Not in Bad Times
提出一个搜寻与匹配模型，其中工作岗位被配给：即使没有匹配摩擦，劳动力市场也不会出清。这种岗位短缺源于工资刚性和劳动边际报酬递减。在经济衰退时，岗位配给严重，推高失业，而匹配摩擦对失业贡献很小。
This paper proposes a search-and-matching model of unemployment in which jobs are rationed: the labor market does not clear in the absence of matching frictions. This job shortage arises in an economic equilibrium from the combination of some wage rigidity and diminishing marginal returns to labor. In recessions, job rationing is acute, driving the rise in unemployment, whereas matching frictions contribute little to unemployment. Intuitively in recessions, jobs are lacking, the labor market is slack, and recruiting is easy and inexpensive, so matching frictions do not matter much. In a calibrated model, cyclical fluctuations in the composition of unemployment are large.