Tying Incentives to Information: Diagnosis-Contingent Contracts and Biased Beliefs in Healthcare
NBER Working Papers · 2026 · Maria Dieci、Paul Gertler、Jonathan T. Kolstad、Carlos Paramo
中文摘要
不必要的治疗反映了患者对自身健康状况的认知与真实病情之间的差距；人们常常针对自己怀疑但并不确知实际患有的疾病寻求并接受治疗。因此，患者对检测价值的评估取决于其对患病的先验信念，而当这些信念存在偏差时，由此产生的检测率可能并非最优，从而造成福利损失。我们研究诊断结果依存型激励契约，即将治疗激励与诊断结果挂钩。对于疟疾，该契约仅对检测结果呈阳性的患者补贴快速诊断检测（RDT）和青蒿素联合疗法（ACT）。在肯尼亚140家药店开展的一项整群随机试验中，患者补贴和服务提供者激励均使检测率大致提高至原来的三倍，并大幅减少了检测阴性患者不必要的ACT购买；二者通过不同渠道发挥作用：患者补贴通过降低价格，服务提供者激励则通过提供信息和建议。一个患者选择模型表明，这些契约带来的社会福利增益远高于其成本。通过对该模型进行结构估计，我们发现，由于患者大幅高估自身感染风险，将激励集中于诊断结果依存型治疗折扣所带来的福利增益，是免费检测项目的四倍。
Abstract
Unnecessary treatment reflects a gap between what patients believe about their health and their true condition; people often seek and consume care for diseases they suspect, but do not know that actually have. The value a patient places on testing therefore depends on their priors about being sick, and when those beliefs are biased, the resulting testing rate might be sub-optimal and leave welfare on the table. We study diagnosis-contingent incentive contracts, which tie treatment incentives to diagnostic results. For malaria, the contract subsidizes rapid diagnostic tests (RDTs) and antimalarials (ACTs) only for patients who test positive. In a cluster-randomized experiment across 140 Kenyan pharmacies, both patient subsidies and provider incentives roughly tripled testing and sharply reduced unnecessary ACT purchases among test-negative patients, working through distinct channels: patient subsidies through lower prices, provider incentives through information and advice. A model of patient choice implies these contracts raise social welfare well above their cost. Estimating the model structurally, we find that because patients substantially overestimate their infection risk, loading incentives onto diagnosis-contingent treatment discounts delivers four times the welfare gains of free testing programs.