n Journal of Minimum Intervention in Dentistry - System research note on : recognizing statistical in-between-trials heterogeneity
|Article Title||System research note on : recognizing statistical in-between-trials heterogeneity|
|© Publisher:||Midentistry CC|
|Journal||Journal of Minimum Intervention in Dentistry|
|Affiliations||1 University of the Witwatersrand|
|Publication Date||Jan 2012|
|Pages||1 - 3|
|Keyword(s)||Clinical trial, Statistical heterogeneity and Systematic reviews|
Context: Quantitative systematic reviews need to consider clinical, methodological and statistical heterogeneity of trials or datasets from trials before combining their results in meta-analyses, as combining results from heterogeneous datasets and / or trials will lead to meaningless results and thus should be avoided. Potential statistical heterogeneity between trials / datasets that have been considered as being clinically / methodologically homogeneous is usually investigated using I2 - test and Cochrane Q statistics.
Problem: However, both, I2 - test and Cochrane Q statistics are tests with low statistical power, which gives even weaker results the smaller the number of trials / datasets is (n < 15).
Suggested solution: Therefore, statistical in-between-trial heterogeneity should be assessed using the point estimate together with its 95% Confidence interval of the I2 - test. Galbraith plots are to be used to identify outlying datasets / trials, which then should be further investigated for potential effect modifiers using regression analysis.
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