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ERIC Number: EJ1015214
Record Type: Journal
Publication Date: 2013-Aug
Pages: 26
Abstractor: As Provided
Reference Count: 22
ISBN: N/A
ISSN: ISSN-1076-9986
Covariate Adjustment Strategy Increases Power in the Randomized Controlled Trial With Discrete-Time Survival Endpoints
Safarkhani, Maryam; Moerbeek, Mirjam
Journal of Educational and Behavioral Statistics, v38 n4 p355-380 Aug 2013
In a randomized controlled trial, a decision needs to be made about the total number of subjects for adequate statistical power. One way to increase the power of a trial is by including a predictive covariate in the model. In this article, the effects of various covariate adjustment strategies on increasing the power is studied for discrete-time survival endpoints; the circumstances are examined under which the covariate adjustment results in a sufficient increase in power. Using a predictive covariate may increase the costs for each subject, so it is useful to quantify when using a covariate is a cost-efficient strategy. The results reveal that using a covariate is highly recommended if the costs for measuring the covariate are relatively small and the correlation with the outcome sufficiently high. (Contains 6 tables and 2 figures.)
SAGE Publications. 2455 Teller Road, Thousand Oaks, CA 91320. Tel: 800-818-7243; Tel: 805-499-9774; Fax: 800-583-2665; e-mail: journals@sagepub.com; Web site: http://sagepub.com
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A