增加现有群组随机试验中的自由度：df* 方法。

Increasing the degrees of freedom in existing group randomized trials: the df* approach.

作者信息

Blitstein Jonathan L, Hannan Peter J, Murray David M, Shadish William R

机构信息

Psychology of Health Behavior Program, RTI International.

出版信息

Eval Rev. 2005 Jun;29(3):241-67. doi: 10.1177/0193841X04273257.

DOI:10.1177/0193841X04273257

PMID:15860765

Abstract

This study describes a method for incorporating external estimates of intraclass correlation to improve the precision for the analysis of an existing group-randomized trial. The authors use a random-effects meta-analytic approach to pool the information across studies, which takes into account any interstudy heterogeneity that may exist. This approach can be used in several different situations to estimate the degrees of freedom available for an adjusted test of the intervention effect in a study where the challenges of group-randomized trials were not fully considered when the study was planned. The authors discuss the limitations of this approach and the circumstances in which it is likely to be helpful.

摘要

本研究描述了一种纳入类内相关外部估计值的方法，以提高对现有群组随机试验分析的精度。作者采用随机效应荟萃分析方法来汇总各项研究的信息，该方法考虑了可能存在的任何研究间异质性。在一项研究中，若在规划时未充分考虑群组随机试验的挑战，此方法可用于几种不同情况，以估计用于干预效果校正检验的自由度。作者讨论了该方法的局限性以及可能有帮助的情况。