Analytical Approximations in Models of Hysteresis
针对不确定性下决策的滞后现象，提出解析近似方法，应用于菜单成本和投资模型，揭示即使小不可逆性也会产生显著滞后效应，菜单成本模型的滞后比传统假设大两个数量级。
Decisions made under ongoing uncertainty and costly reversibility entail a range of the state variable where inaction is optimal, which in turn produces hysteresis—permanent effects of temporary shifts. The range is usually defined by non-linear equations that need numerical solutions. In this paper a technique of analytical approximations is developed and applied to two models—menu costs and investment. The resulting explicit solutions help clarify why hysteresis is important even for small irreversibility. In the menu cost model, hysteresis is two orders of magnitude larger than under the Akerlof-Yellen or Mankiw assumptions.