Fluctuations in Equilibrium Unemployment
指出理解均衡失业率波动需要解释为何在均衡条件下仍有失业，重点研究工人最初失业的原因，并基于标准方法构建了就业持续期的理论模型。
Fluctuations in the equilibrium rate of unemployment can only be understood within a of the natural or equilibrium rate. It is not enough to say that unemployment is the difference between supply and demand in the labor market, though of course it always will be. In equilibrium, no participants in the market can have an unexploited opportunity to make themselves better off. At the equilibrium unemployment rate, employers cannot obtain labor at lower cost by offering work at below the market wage to the unemployed. Unemployed workers cannot raise their effective real incomes by taking lower wages in exchange for immediate employment. The task of the is to explain why any unemployment remains at all when these conditions are satisfied. Part of this problem has been studied in detail in the search theory of unemployment -- once a worker becomes unemployed, it is reasonably well understood why the worker does not become employed again immediately. The of why people become unemployed in the first place is less well developed and is the main concern of this paper. Most of the unemployed are looking for new work because their previous jobs ran out. Consequently, the main ingredient of a of the flow of workers into unemployment is a of the duration of employment. Such a is developed here, along reasonably standard lines.