Work

Sample size estimation in educational intervention trials with subgroup heterogeneity in only one arm

Year: 2012

Type: article

Abstract: We present closed form sample size and power formulas motivated by the study of a psycho-social intervention in which the experimental group has the intervention delivered in teaching subgroups whereas the control group receives usual care. This situation is different from the usual clustered randomized trial because subgroup heterogeneity only exists in one arm. We take this modification into consideration and present formulas for the situation in which we compare a continuous outcome at both a single point in time and longitudinally over time. In addition, we present the optimal combination of parameters such as the number of subgroups and number of time points for minimizing sample size and maximizing power subject to constraints such as the maximum number of measurements that can be taken (i.e., a proxy for cost).

Source: Statistics in Medicine

DOI: 10.1002/sim.5678

Authors: Denise Esserman, Yingqi Zhao, Yiyun Tang, Jianwen Cai

Institutions: University of North Carolina at Chapel Hill, University of Wisconsin–Madison, Pfizer (United States)

Language: English

Topic: Statistical Methods in Clinical Trials

Subfield: Statistics and Probability

Field: Mathematics

Domain: Physical Sciences

Open Access status: green

Funders: National Institutes of Health, National Heart, Lung, and Blood Institute, National Cancer Institute, National Center for Research Resources