Power and Money: Designing Statistically Powerful Studies while Minimizing Financial Costs

Adequate statistical power is increasingly demanded in research design. However, obtaining adequate research funding is increasingly difficult. This places researchers in a difficult position. In response, the authors advocate an approach to designing studies that considers statistical power and financial concerns simultaneously. Their purpose is twofold: (a) to introduce the general paradigm of cost optimization in the context of power analysis and (b) to present techniques for such optimization. Techniques are presented in the context of a randomized clinical trial. The authors consider (a) selecting optimal cutpoints for subject screening tests; (b) optimally allocating subjects to different treatment conditions; (c) choosing between obtaining more subjects or taking more replicate measurements; and (d) using prerandomization covariates.