论文标题
针对仪器的治疗效果
Treatment Effects with Targeting Instruments
论文作者
论文摘要
在应用中，多相的治疗是司空见惯的。我们探讨了在这种情况下使用离散价值仪器来控制选择偏差的使用。我们的讨论围绕定位概念：哪些仪器针对哪些治疗方法。它使我们能够建立反事实平均值和治疗效果的条件。我们通过将其应用于Head Start Impact研究中的数据来说明我们的框架的有用性。在合理的积极选择假设下，我们得出了信息界的范围，这些界限比Kline和Walters（2016）的参数估计值表明，头开始扩展的有益效果较小。
Multivalued treatments are commonplace in applications. We explore the use of discrete-valued instruments to control for selection bias in this setting. Our discussion revolves around the concept of targeting: which instruments target which treatments. It allows us to establish conditions under which counterfactual averages and treatment effects are point- or partially-identified for composite complier groups. We illustrate the usefulness of our framework by applying it to data from the Head Start Impact Study. Under a plausible positive selection assumption, we derive informative bounds that suggest less beneficial effects of Head Start expansions than the parametric estimates of Kline and Walters (2016).
