当前位置: X-MOL 学术Evaluation Review › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Statistical Power for the Comparative Regression Discontinuity Design With a Pretest No-Treatment Control Function: Theory and Evidence From the National Head Start Impact Study.
Evaluation Review ( IF 3.0 ) Pub Date : 2018-02-01 , DOI: 10.1177/0193841x18776117
Yang Tang 1 , Thomas D Cook 1, 2
Affiliation  

The basic regression discontinuity design (RDD) has less statistical power than a randomized control trial (RCT) with the same sample size. Adding a no-treatment comparison function to the basic RDD creates a comparative RDD (CRD); and when this function comes from the pretest value of the study outcome, a CRD-Pre design results. We use a within-study comparison (WSC) to examine the power of CRD-Pre relative to both basic RDD and RCT. We first build the theoretical foundation for power in CRD-Pre, then derive the relevant variance formulae, and finally compare them to the theoretical RCT variance. We conclude from this theoretical part of this article that (1) CRD-Pre’s power gain depends on the partial correlation between the pretest and posttest measures after conditioning on the assignment variable, (2) CRD-Pre is less responsive than basic RDD to how the assignment variable is distributed and where the cutoff is located, and (3) under a variety of conditions, the efficiency of CRD-Pre is very close to that of the RCT. Data from the National Head Start Impact Study are then used to construct RCT, RDD, and CRD-Pre designs and to compare their power. The empirical results indicate (1) a high level of correspondence between the predicted and obtained power results for RDD and CRD-Pre relative to the RCT, and (2) power levels in CRD-Pre and RCT that are very close. The study is unique among WSCs for its focus on the correspondence between RCT and observational study standard errors rather than means.

中文翻译:

具有预测试无处理控制功能的比较回归非连续性设计的统计功效:来自全国领先影响研究的理论和证据。

基本回归不连续性设计(RDD)的统计功效比具有相同样本量的随机对照试验(RCT)的统计功效低。在基本RDD上添加免处理比较功能会创建比较RDD(CRD);当此功能来自研究结果的预测试值时,将得出CRD-Pre设计。我们使用研究内比较(WSC)来检查CRD-Pre相对于基本RDD和RCT的功能。我们首先为CRD-Pre中的功率建立理论基础,然后推导相关的方差公式,最后将其与RCT的理论方差进行比较。我们从本文的理论部分得出结论:(1)CRD-Pre的功率增益取决于分配变量为条件后的前测和后测度量之间的部分相关性,(2)CRD-Pre对分配变量的分布方式以及截止位置的响应性不如基本RDD;(3)在多种条件下,CRD-Pre的效率与RCT的效率非常接近。然后,将来自全国领先影响研究的数据用于构建RCT,RDD和CRD-Pre设计并比较其功能。实验结果表明:(1)RDD和CRD-Pre的预测功率结果和获得的功率结果相对于RCT的对应程度很高,(2)CRD-Pre和RCT的功率水平非常接近。这项研究在WSC中是独特的,因为它着重于RCT与观察性研究标准误差之间的对应关系,而不是均值。CRD-Pre的效率非常接近RCT。然后,将来自全国领先影响研究的数据用于构建RCT,RDD和CRD-Pre设计并比较其功能。实验结果表明:(1)RDD和CRD-Pre的预测功率结果和获得的功率结果相对于RCT的对应程度很高,(2)CRD-Pre和RCT的功率水平非常接近。这项研究在WSC中是独特的,因为它着重于RCT与观察性研究标准误差之间的对应关系,而不是均值。CRD-Pre的效率非常接近RCT。然后,将来自全国领先影响研究的数据用于构建RCT,RDD和CRD-Pre设计并比较其功能。实验结果表明:(1)RDD和CRD-Pre的预测功率结果和获得的功率结果相对于RCT的对应程度很高,(2)CRD-Pre和RCT的功率水平非常接近。这项研究在WSC中是独特的,因为它着重于RCT与观察性研究标准误差之间的对应关系,而不是均值。实验结果表明:(1)RDD和CRD-Pre的预测功率结果和获得的功率结果相对于RCT的对应程度很高,(2)CRD-Pre和RCT的功率水平非常接近。这项研究在WSC中是独特的,因为它着重于RCT与观察性研究标准误差之间的对应关系,而不是均值。实验结果表明:(1)RDD和CRD-Pre的预测功率结果和获得的功率结果相对于RCT的对应程度很高,(2)CRD-Pre和RCT的功率水平非常接近。这项研究在WSC中是独特的,因为它着重于RCT与观察性研究标准误差之间的对应关系,而不是均值。
更新日期:2018-02-01
down
wechat
bug