A Reason for Quantity Regulation
解释为何政府常选择数量管制而非税收来监管金融中介、捕鱼、污染等，关键在于违规行为比逃税更容易被发现，即使无执行成本时税收更优。
Contrary to the standard economic advice, many regulations of financial intermediaries, as well as other regulations such as blue laws, fishing rules, zoning restrictions, or pollution controls, take the form of quantity controls rather than taxes. We argue that costs of enforcement are crucial to understanding these choices. When violations of quantity regulations are cheaper to discover than failures to pay taxes, the former can emerge as the optimal instrument for the government, even when it is less attractive in the absence of enforcement costs. This analysis is especially relevant to situations where private enforcement of regulations is crucial.