More Powerful Cluster Randomized Controlled Trials
本文提出在整群随机对照试验中，当处理组成本高于对照组时，如何灵活选择处理组和对照组的群组数量及群内单位数，以最大化统计功效。基于三个发展经济学实例，功效提升在7.9到19.0个百分点之间。
Balanced experimental designs, in which the number of treatment and control units are the same, do not maximize power subject to a cost constraint when treatment units are more expensive than control ones. Despite this, such balanced designs are the norm in economics. This paper describes methods to optimally choose the number of treatment and control clusters, and the number of units within treatment and control clusters, allowing for full flexibility. We use three archetypal examples from the development literature to illustrate the magnitude of the power gains, which lie between 7.9 and 19.0 percentage points.