Gabriel Chodorow-Reich, Loukas Karabarbounis. 2013. The cyclicality of the opportunity cost of employment. Working Paper 19678. National Bureau of Economic Research

http://www.nber.org/papers/w19678

Abstract: The flow opportunity cost of moving from unemployment to employment consists of foregone public benefits and foregone utility from non-working time relative to consumption. Using detailed microdata, administrative data, and the structure of the search and matching model with concave and non-separable preferences, we document that the opportunity cost of employment is as procyclical as, and more volatile than, the marginal product of employment. The empirically-observed cyclicality of the opportunity cost implies that unemployment volatility in search and matching models of the labor market is far smaller than that observed in the data. This result holds irrespective of the level of the opportunity cost or whether wages are set by Nash bargaining or by an alternating-offer bargaining process. We conclude that appealing to aspects of labor supply does not help search and matching models explain aggregate employment fluctuations.

摘要：从非就业到就业转移的流动机会成本包含了非工作时间中与消费有关的预先公共收益与预先效用。使用细致的微观数据、管理数据与搜寻匹配理论结构、凹形和不可分的偏好，我们发现就业的机会成本与就业的边际产品一样呈顺势循环，且更为猛烈。实证观察到的机会成本的周期性表明劳动力市场的搜寻匹配模型失业波动性远比在数据中观察到的小。这个结论不考虑机会成本的水平及工资是否是由纳什议价或交互议价过程产生的。我们可以归纳说诉诸劳动力供给并不能帮助搜寻匹配理论解释总体就业波动。

数据来源： We construct a dataset of U.S. time series at quarterly frequency between 1961(1) and 2012(4). We use the HP-_lter to detrend variables.

研究方法：计量回归

Conclusion: This paper has shown that the flow value of the opportunity cost of employment falls during recessions. The key mechanism is that the household values most the contribution of the employed (through higher wage income) relative to that of the unemployed (through higher non-working time) when market consumption is low and non-working time is high. This more than offsets the effect of the increase in government benefits. Our preferred estimate of the elasticity of the opportunity cost with respect to the marginal product of employment is unity. With this value, fluctuations in unemployment generated by the model are essentially neutral with respect to the level of z, and remain far smaller than unemployment fluctuations in the data.

An interpretation of our results is that endogenous forms of wage rigidity, such as accomplished by Hagedorn and Manovskii (2008) and by Hall and Milgrom (2008), do not survive the introduction of a cyclical flow opportunity cost. Without rigid wages, these models cannot generate volatile unemployment. This pessimistic conclusion does not apply to models where wages are exogenously sticky or selected according to some process that does not depend on worker's opportunity cost of employment. The extent to which actual wages vary cyclically remains an open and important question.

Our quantitative results also apply only to the extensive margin of labor supply. The same economic reasoning that makes the extensive margin choice sensitive to the marginal utility of consumption relative to the value of non-working time would also affect the intensive margin choice. However, we have not modeled the complicated set of benefit phase-out schedules that give rise to high implicit marginal tax rates at the low end of the income distribution (Mulligan, 2012), and so cannot say quantitatively whether cyclical variation in benefits phase-outs overwhelms the effect of the higher marginal utility of consumption relative to the value of non-working time during recessions.

结论：这篇文章展现了衰退中就业机会成本的流动价值。关键的机制是：当市场消费低、非工作时间高时，相比其失业（通过更多的非工作时间），家庭更看重就业的贡献（通过更高的工资收入）。这点能够冲抵政府收益的影响。我们假设机会成本对边际产品的弹性即是效用。根据这点，由模型引起的失业波动对z保持中性，且远比数据中失业的波动要小。

一种对我们的成果的解释是：内生的工资刚性不能一直存在于周期性机会成本中，譬如Hagedorn与 Manovskii (2008) 和Hall与Milgrom (2008)的理论。不考虑刚性工资，这个模型不能衍生出剧烈的失业。这个消极的结论不能支持模型——工资是具有外生粘性或跟据一些不依赖工人就业的机会成本的流程被选择的。工资周期性变化的范围仍然是个开放且重要的问题。

我们的量化结果也仅仅适用于劳动力供给的粗放边际。同样的经济可以推理：对于非工作时间的价值消费边际收益敏感的粗放边际选择也可能影响集约边际选择。然而，我们没有对逐步削减收益的在收入分配的低水平上引起高隐含边际税率的计划进行建模，也因此不能说在量上收益的周期性波动逐渐盖过消费的高边际效应的影响（相对于萧条期非工作时间价值）。

（By 潘一坤)