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

TitleSample size estimation in educational intervention trials with subgroup heterogeneity in only one arm.
Publication TypeJournal Article
Year of Publication2013
AuthorsEsserman, Denise, Yingqi Zhao, Yiyun Tang, and Jianwen Cai
JournalStat Med
Volume32
Issue12
Pagination2140-54
Date Published2013 May 30
ISSN1097-0258
KeywordsComputer Simulation, Hepacivirus, Hepatitis C, Humans, Longitudinal Studies, Randomized Controlled Trials as Topic, Research Design, Sample Size
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).

DOI10.1002/sim.5678
Alternate JournalStat Med
Original PublicationSample size estimation in educational intervention trials with subgroup heterogeneity in only one arm.
PubMed ID23172724
PubMed Central IDPMC3615113
Grant ListR01 HL057444 / HL / NHLBI NIH HHS / United States
P01CA142538 / CA / NCI NIH HHS / United States
UL1RR025747 / RR / NCRR NIH HHS / United States
UL1 RR025747 / RR / NCRR NIH HHS / United States
R01HL57444 / HL / NHLBI NIH HHS / United States
P01 CA142538 / CA / NCI NIH HHS / United States
Project: