The Ins and Outs of Cyclical Unemployment
回顾几十年实证文献，用对数变化分解法分析战后每次衰退中失业的上升，指出理解周期性失业必须同时解释失业流入率的逆周期性和流出率的顺周期性。
A dominant trend in recent modeling of labor market fluctuations is to treat unemployment inflows as acyclical. This trend has been encouraged by recent influential papers that stress the role of longer unemployment spells, rather than more unemployment spells, in accounting for recessionary unemployment. After reviewing an empirical literature going back several decades, we apply a convenient log change decomposition to Current Population Survey data to characterize rising unemployment in each postwar recession. We conclude that a complete understanding of cyclical unemployment requires an explanation of countercyclical inflow rates, especially for job losers (layoffs), as well as procyclical outflow rates.