Nonstationarity in Job Search Theory
研究求职模型中所有外生变量（如失业时长）导致非平稳性的情况，推导出保留工资随时间变化的微分方程，并估计一个非平稳模型，发现福利水平下降后的失业时长弹性远大于下降前。
Generally, structural job search models are taken to be stationary. In this paper models are examined in which every exogenous variable can cause nonstationarity, for instance because its value is dependent on unemployment duration. A general differential equation that describes the evolution of the reservation wage over time is derived. As an empirical illustration a nonstationary structural model is estimated that focuses on the consequences of a downward shift in the level of benefits. It appears that the elasticity of duration with respect to the level of benefits after the shift is much larger than the elasticity with respect to the level before the shift.