The Benefit Offset National Demonstration (BOND) tested a $1 reduction in benefits per $2 earnings increase above the level at which Social Security Disability Insurance benefits drop from full to zero under current law. BOND included a rare and large “population-representative” experiment: It applied the rule to a nationwide, random sample of beneficiaries. BOND also included a parallel “volunteer” experiment: The same offset rules applied to a nationwide random sample of volunteers. BOND’s dual experiments offer a unique opportunity to consider the merits and limitations of these two types of experiments. The findings provide a way to illustrate the limitations of volunteer experiments relative to population experiments when, as in BOND, the goal is to produce impact estimates that are valid for the entire population, not just would be volunteers. We also highlight and compare ethical issues, outreach challenges, and cost considerations for the two types of designs.

中文翻译：

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人口代表性实验和志愿者实验的比较：社会保障局福利抵消全国示范 (BOND) 的经验教训

福利抵消全国示范 (BOND) 测试了在社会保障残疾保险福利根据现行法律从全额降至零的水平之上，收入每增加 2 美元，福利减少 1 美元。BOND 包括一个罕见的大型“人口代表”实验：它将规则应用于全国范围的随机受益人样本。BOND 还包括一个平行的“志愿者”实验：同样的抵消规则适用于全国范围的志愿者随机样本。BOND 的双重实验提供了一个独特的机会来考虑这两种类型的实验的优点和局限性。研究结果提供了一种方法来说明志愿者实验相对于群体实验的局限性，就像在 BOND 中一样，目标是产生对整个群体有效的影响估计，不仅仅是志愿者。我们还强调并比较了这两种设计的伦理问题、外展挑战和成本考虑。