This article examines the consequences and causes of low enrollment of Black patients in clinical trials. We develop a simple model of similarity-based extrapolation that predicts that evidence is more relevant for decision-making by physicians and patients when it is more representative of the group that is being treated. This generates the key result that the perceived benefit of a medicine for a group depends not only on the average benefit from a trial, but also on the share of patients from that group who were enrolled in the trial. In survey experiments, we find that physicians who care for Black patients are more willing to prescribe drugs tested in representative samples, an effect substantial enough to close observed gaps in the prescribing rates of new medicines. Black patients update more on drug efficacy when the sample that the drug is tested on is more representative, reducing Black-White patient gaps in beliefs about whether the drug will work as described. Despite these benefits of representative data, our framework and evidence suggest that those who have benefited more from past medical breakthroughs are less costly to enroll in the present, leading to persistence in who is represented in the evidence base.

中文翻译：

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表征和外推：临床试验的证据

本文探讨了临床试验中黑人患者入组率低的后果和原因。我们开发了一个基于相似性的简单外推模型，该模型预测当证据更能代表正在接受治疗的群体时，证据与医生和患者的决策更相关。这产生了一个关键结果，即药物对一个群体的感知益处不仅取决于试验的平均益处，还取决于该群体参加试验的患者比例。在调查实验中，我们发现照顾黑人患者的医生更愿意开出经过代表性样本测试的药物，这种效果足以弥补观察到的新药处方率差距。当测试药物的样本更具代表性时，黑人患者会更多地了解药物疗效，从而减少黑人和白人患者对药物是否如所描述的那样起作用的信念差距。尽管代表性数据有这些好处，但我们的框架和证据表明，那些从过去的医学突破中受益更多的人现在的注册成本较低，从而导致证据库中代表的人持续存在。