City Research Online

Abstract

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.

Publication Type:	Article
Additional Information:	The completed version of record is expected to be published with DOI https://doi.org/10.1086/739610 in an upcoming issue of Economic Development and Cultural Change, published by The University of Chicago Press. Copyright 2025 The University of Chicago.
Publisher Keywords:	Power analysis, Sample size calculations, Randomized Control Trials, Cluster Randomized Control Trials
Subjects:	H Social Sciences > H Social Sciences (General) H Social Sciences > HB Economic Theory
Departments:	School of Policy & Global Affairs School of Policy & Global Affairs > Department of Economics
SWORD Depositor:	Symplectic Administrator

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