Are We Worse Off After Policy Repeals? Evidence from Two Green Policies
研究两项环保政策（禁塑令和塑料袋收费）废除后，政策实施期间产生的溢出效应（如垃圾袋销量增加）是否持续存在，发现这种效应在废除后仍持续数月，但净环境效益可能仍为正。
Implementation of public policies sometimes results in spillover effects on nontargeted outcomes. When policy makers repeal these policies due to industry pressure and community resistance, do the spillover effects from the policy persist after a repeal? Specifically, the authors ask (1) whether these spillovers induced by policy, when present, carry on after a repeal (i.e., become “carryovers”); (2) how these carryovers evolve over the short and medium term; and (3) what benefit thresholds the policy must meet to offset spillovers during implementation and carryovers after repeal. To address these questions, the authors examine two pro-environment policies that were later repealed: a ban on single-use plastic grocery bags and the imposition of a fee. They find that the increase in trash bag sales, which began during policy implementation, persisted for several months after repeal. A break-even analysis suggests that the net effect on plastic bag savings is likely positive even after repeal. Only modest reductions in grocery bag use would be needed to break even, suggesting a favorable outcome for the environment. This study alerts policy makers and firms to potential carryovers from policy repeals that can persist well after a repeal.