Counterfactual assessment techniques involving treated and control groups, such as randomized control trials, might be used in outcome-based contracts to avoid rewarding or sanctioning service providers for social outcomes that they did not cause. However, few outcome-based contracts adopt payment rules based on counterfactual assessment techniques. Potential explanations are that these techniques are complex and involve substantial transaction costs. In this paper, we develop a theoretical formal model that integrates the literatures of incentives and policy evaluation to propose the following alternative explanation: counterfactual techniques may lead to counterproductive incentive effects if they reduce the likelihood of payment even if project managers exert sufficient effort to promote the expected interventions. Our model shows that counterfactual assessment may undermine effort when the number of treated subjects is small and there is limited investment per treated subject. Our formal model also suggests that the increased experience of the contract sponsors may inhibit the adoption of counterfactual assessment. Simulations and descriptive evidence from a unique database of 350 outcome-based contracts designed or initiated throughout the world and from linear probability models are aligned with our predictions. By offering additional explanations on why counterfactual assessment methods are not widespread in outcome-based contracts and by identifying the boundary conditions under which these methods are used in incentive contracts, this work informs the literature on cross-sector outcome-based contracts and illustrates the use of formal models to develop novel theories in public administration.

中文翻译：

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为什么反事实评估方法在基于结果的合同中没有广泛使用？正式的模型方法

涉及治疗组和对照组的反事实评估技术，例如随机对照试验，可用于基于结果的合同，以避免因服务提供者没有引起的社会结果而奖励或制裁服务提供者。然而，很少有基于结果的合同采用基于反事实评估技术的支付规则。可能的解释是这些技术很复杂并且涉及大量交易成本。在本文中，我们开发了一个理论形式模型，整合了激励和政策评估的文献，提出了以下替代解释：即使项目经理付出足够的努力来促进支付的可能性，反事实技术也可能导致适得其反的激励效应。预期的干预措施。我们的模型表明，当治疗对象的数量很少且每个治疗对象的投资有限时，反事实评估可能会破坏努力。我们的正式模型还表明，合同发起人的经验增加可能会抑制采用反事实评估。来自世界各地设计或发起的 350 份基于结果的合同的独特数据库以及线性概率模型的模拟和描述性证据与我们的预测一致。通过提供额外的解释说明为什么反事实评估方法在基于结果的合同中并不普遍，并通过确定这些方法在激励合同中使用的边界条件，