Research article summary (published 27 Feb 1995):

Group sequential comparison of changes: ad-hoc versus more exact method.

Full Abstract

There are many clinical trials in which we are interested in comparing changes in responses between two treatment groups sequentially. Investigators might assume a simple linear model, take the average of the ordinary least square estimators of slope within each treatment group, and use the standardized difference between these two averages as the test statistic at each interim analysis. Ad-hoc construction of the boundary values for interim analysis might be based on group sequential methods which assume that the interim test statistics have independent increments even though it may not be true when a response variable is measured repeatedly over time for each subject. This ad-hoc method is very simple and appealing, and thus has been used in a clinical trial setting. Lee and DeMets (1991, Journal of the American Statistical Association 86, 757-762) have proposed a more exact group sequential method for comparing rates of change. Under the assumption that the response follows the linear mixed effects model, they have derived the asymptotic joint distribution of the sequentially computed statistics. Construction of group sequential boundaries is based on this distribution theory. By simulation studies, we first study the robustness of the more exact method to violations of the typical assumptions. In addition, we compare the ad-hoc method with the more exact method and examine how well these two methods work for various situations. The relationship between two different information times, Fisher information and a surrogate information, are also discussed from the simulation studies.

Author information

Author/s: Lee, J W (JW); DeMets, D L (DL);

Affiliation: Department of Statistics, Korea University, Seoul.

Grants: R01-CA-13539 (Agency:NCI NIH HHS) ; R01-CA-18332 (Agency:NCI NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.

Journal: Biometrics (Biometrics), published in UNITED STATES. (Language: eng)

Reference: 1995-Mar; vol 51 (issue 1) : pp 21-30

Dates: Created 1995/06/30; Completed 1995/06/30; Revised 2007/11/15;

PMID: 7766776, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Analysis of Variance Biometry - methods Clinical Trials as Topic - methods Humans

Humans Models, Statistical National Institutes of Health (U.S.) United States

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