We propose informational spillovers as a new rationale for the use of multiple policy instruments to mitigate a single externality. We investigate the design of a pollution standard when the firms’ abatement costs are unknown and emissions are taxed. A firm might abate pollution beyond what is required by the standard by equalizing its marginal abatement costs to the tax rate, thereby revealing information about its abatement cost. We analyze how a regulator can take advantage of this information to design the standard. In a dynamic setting, the regulator relaxes the initial standard in order to induce more information revelation, which would allow her to set a standard closer to the first best in the future. Updating standards, though, generates a ratchet effect since a low-cost firm might strategically hide its cost by abating no more than required by the standard. We characterize the optimal standard and its update across time depending on the firm’s abatement strategy. We illustrate our theoretical results with the case of NO_x regulation in Sweden. We find evidence that the firms that pay the NO_x tax experience more frequent standard updates and more stringent revisions than those who are exempted.

我们建议将信息溢出作为使用多种政策工具减轻单一外部性的新原理。当企业的减排成本未知且对排放征税时，我们将研究污染标准的设计。企业可以通过将其边际减排成本与税率相等来减轻污染，使其超出标准所要求的水平，从而揭示有关其减排成本的信息。我们分析了监管机构如何利用这些信息来设计标准。在动态环境中，监管机构放宽了初始标准，以引发更多的信息披露，这将使她可以将标准设定为更接近将来的最佳水平。不过，更新标准 之所以会产生棘轮效应，是因为低成本公司可能会通过削减不超过标准要求的数量来从战略上隐藏其成本。我们根据企业的减排策略来确定最佳标准及其随时间的更新。我们以否为例说明我们的理论结果_x瑞典的法规。我们发现证据表明，支付NO的公司_X税的经验更频繁更新的标准和更严格的版本比那些被免除谁。