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ERIC Number: EJ1119691
Record Type: Journal
Publication Date: 2016-Dec
Pages: 23
Abstractor: As Provided
ISSN: ISSN-1076-9986
Power for Detecting Treatment by Moderator Effects in Two- and Three-Level Cluster Randomized Trials
Spybrook, Jessaca; Kelcey, Benjamin; Dong, Nianbo
Journal of Educational and Behavioral Statistics, v41 n6 p605-627 Dec 2016
Recently, there has been an increase in the number of cluster randomized trials (CRTs) to evaluate the impact of educational programs and interventions. These studies are often powered for the main effect of treatment to address the "what works" question. However, program effects may vary by individual characteristics or by context, making it important to also consider power to detect moderator effects. This article presents a framework for calculating statistical power for moderator effects at all levels for two- and three-level CRTs. Annotated R code is included to make the calculations accessible to researchers and increase the regularity in which a priori power analyses for moderator effects in CRTs are conducted.
SAGE Publications. 2455 Teller Road, Thousand Oaks, CA 91320. Tel: 800-818-7243; Tel: 805-499-9774; Fax: 800-583-2665; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: National Science Foundation (NSF)
Authoring Institution: N/A
Grant or Contract Numbers: DGE1437679; DGE1437692; DGE1437745