Collective Payments for Ecosystem Services (PES), where forest users receive compensation conditional on group rather than individual performance, are an increasingly used policy instrument to reduce tropical deforestation. However, implementing effective, (cost) efficient and equitable (3E) collective PES is challenging because individuals have an incentive to free ride on others’ conservation actions. Few comparative studies exist on how different enforcement strategies can improve collective PES performance. We conducted a framed field experiment in Brazil, Indonesia and Peru to evaluate how three different strategies to contain the local free-rider problem perform in terms of the 3Es: (i) Public monitoring of individual deforestation, (ii) internal, peer-to-peer sanctions (Community enforcement) and (iii) external sanctions (Government enforcement). We also examined how inequality in wealth, framed as differences in deforestation capacity, affects policy performance. We find that introducing individual level sanctions can improve the effectiveness, efficiency and equity of collective PES, but there is no silver bullet that consistently improves all 3Es across country sites. Public monitoring reduced deforestation and improved the equity of the program in sites with stronger history of collective action. External sanctions provided the strongest and most robust improvement in the 3Es. While internal, peer enforcement can significantly reduce free riding, it does not improve the program’s efficiency, and thus participants’ earnings. The sanctioning mechanisms failed to systematically improve the equitable distribution of benefits due to the ineffectiveness of punishments to target the largest free-riders. Inequality in wealth increased group deforestation and reduced the efficiency of Community enforcement in Indonesia but had no effect in the other two country sites. Factors explaining differences across country sites include the history of collective action and land tenure systems.

生态系统服务集体支付（PES），森林使用者根据集体而不是个人的表现获得补偿，是一种越来越多地用于减少热带森林砍伐的政策工具。然而，实施有效、（成本）高效和公平（3E）的集体 PES 具有挑战性，因为个人有动力搭便车搭便车他人的保护行动。很少有关于不同执法策略如何提高集体 PES 绩效的比较研究。我们在巴西、印度尼西亚和秘鲁进行了一项框架式实地实验，以评估三种不同的遏制当地搭便车问题的策略在 3E 方面的表现：(i) 对个体森林砍伐的公共监测，(ii) 点对点制裁（社区执法）和 (iii) 外部制裁（政府执法）。我们还研究了财富不平等如何以森林砍伐能力的差异为框架,影响政策绩效。我们发现，引入个人层面的制裁可以提高集体 PES 的有效性、效率和公平性，但没有灵丹妙药可以持续改善国家/地区的所有 3E。公共监督减少了森林砍伐并提高了该计划在集体行动历史悠久的地点的公平性。外部制裁在 3E 中提供了最强劲和最强劲的改进。虽然内部的同行执法可以显着减少搭便车，但它不会提高计划的效率，从而提高参与者的收入。由于针对最大的搭便车者的惩罚无效，制裁机制未能系统地改善利益的公平分配。财富不平等加剧了集体砍伐森林并降低了印度尼西亚社区执法的效率，但对其他两个国家/地区没有影响。解释不同国家地点差异的因素包括集体行动的历史和土地权属制度。