This article analyzes the optimal combination of ex ante and ex post regulation of an activity in a two-period model. Additional information about the sign and extent of the externality associated with the activity becomes available only once a private party undertakes the activity, but undoing the activity at that stage is costly. We characterize when the regulator should commit not to reevaluate the activity ex post. The case for ex post regulation is strengthened if the private party can signal its private information about the consequences of the activity, but it is weakened if the cost of undoing the activity can be manipulated.

中文翻译：

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批准监管和学习，以及合并控制时间的应用

本文分析了两期模型中一项活动的事前和事后监管的最佳组合。有关与活动相关的外部性的迹象和程度的更多信息只有在私人方开展活动后才能获得，但在该阶段取消活动的成本很高。我们描述了监管机构何时应承诺不事后重新评估活动。如果社会资本可以发出有关活动后果的私人信息，则事后监管的理由会得到加强，但如果取消活动的成本可以被操纵，事后监管的理由就会被削弱。