Estimating Decision-Relevant Comparative Effects Using Instrumental Variables.
Estimating Decision-Relevant Comparative Effects Using Instrumental Variables.
复制标题
DOI：
10.1007/s12561-011-9033-6
复制
发表时间：
2011-09
影响因子：
1
通讯作者：
Basu, Anirban
中科院分区：
文献类型：
--
作者：
Basu, Anirban
工具变量方法（IV）在卫生经济学文献中被广泛用于在估计治疗效果时调整观察性研究中的隐藏选择偏差。在应用文献中，如果治疗效果在不同受试者之间是异质的，则对静脉注射的正确使用关注较少。当个体对治疗的自我选择与治疗的预期特殊收益或损失相关时，这种效果的异质性成为IV估计者的一个问题。我们概述了在存在效应异质性和自我选择的情况下，IV估计器所面临的挑战，并将传统的IV分析与使用IV直接解决这些挑战的替代方法进行了比较。我们使用临床局限性乳腺癌患者的医疗保险样本，研究保乳手术和乳房切除术放疗对3年生存率的影响。我们的研究结果显示，传统的静脉注射结果可能掩盖了治疗效果的重要异质性。在这些结果的背景下，我们讨论了传统和替代IV方法在估计平均治疗效果参数方面的优势和局限性，异质性在比较有效性研究中的作用以及对技术扩散的影响。
Instrumental variables methods (IV) are widely used in the health economics literature to adjust for hidden selection biases in observational studies when estimating treatment effects. Less attention has been paid in the applied literature to the proper use of IVs if treatment effects are heterogeneous across subjects. Such a heterogeneity in effects becomes an issue for IV estimators when individuals’ self-selected choices of treatments are correlated with expected idiosyncratic gains or losses from treatments. We present an overview of the challenges that arise with IV estimators in the presence of effect heterogeneity and self-selection and compare conventional IV analysis with alternative approaches that use IVs to directly address these challenges. Using a Medicare sample of clinically localized breast cancer patients, we study the impact of breast-conserving surgery and radiation with mastectomy on 3-year survival rates. Our results reveal the traditional IV results may have masked important heterogeneity in treatment effects. In the context of these results, we discuss the advantages and limitations of conventional and alternative IV methods in estimating mean treatment-effect parameters, the role of heterogeneity in comparative effectiveness research and the implications for diffusion of technology.