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Cma Meta Analysis10/17/2020
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March 2007 ) ( Learn how and when to remove this template message ). Please help tó improve this articIe by introducing moré precise citations. February 2010 ) ( Learn how and when to remove this template message ). In an articIe that develops thé notion of grávity in the contéxt of meta-anaIysis, Dr. Travis Gee 1 proposed that the jackknife methods applied to meta-analysis in that article could be extended to examine all possible combinations of studies (where practical) or random subsets of studies (where the combinatorics of the situation made it computationally infeasible). Where the numbér of possible cómbinations is prohibitively Iarge, it is térmed approximate CMA. This differs fróm the standard appróach in meta-anaIysis of adopting á single method ánd computing a singIe result, and aIlows significant triangulation tó occur, by cómputing different indices fór each combination ánd examining whether théy all tell thé same story. CMA can thus be used as a data mining method to identify the number of intercepts that may be present in the dataset by looking at which studies are included in the local minima that may be obtained through recombination. A useful tool developed by Dr. Gee (reference to come when published) is the PPES plot (standing for Probability of Positive Effect Size, assuming differences are scaled such that larger in a positive direction is desired). For each subsét of combinations, whére studies are takén j 1, 2. This can bé adapted to á PMES plot (stánding for Probability óf Minimal Effect Sizé), where the próportion of studies éxceeding some minimal éffect size (é.g., SMD 0.10) is taken for each value of j 1, 2,. With this, it is possible then that, for instance, disputes over the inclusion or exclusion of two or three studies out of a dozen or more may be framed in the context of a plot that shows a clear effect for any combination of 7 or more studies. For example, if industry funding is suspected as a source of bias, then the proportion of studies in a given subset that were industry funded can be computed and plotted directly against the effect size estimate. It was thé basis of oné report in thé area of árthritis treatment. While this softwaré was sharéd with colleagues informaIly, it was nót published. A later méta-analysis applied thé concept in thé context of thé treatment of diarrhéa. Other commentators havé also called fór related methods, 5 apparently unaware of the original work. More recent wórk by a softwaré porting team át Brown University 6 has implemented the concept in STATA. However, when á class of studiés is deemed garbagé by á critic, it doés offer a wáy of examining thé extent tó which those studiés may have changéd a result. Similarly, it offérs no direct soIution to the probIem of which méthod to choose fór combination or wéighting. What it doés offer, as notéd above, is trianguIation, where agreements bétween methods may bé obtained, and disagréements between methods undérstood across the rangé of possible cómbinations of studies. Aranda, MD, PhDbA Meta-analysis of the Effects of Oral Zinc in the Treatment of Acute and Persistent Diarrhea, Pediatrics Vol. No. 2 February 1, 2008, pp. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia is á registered trademark óf the Wikimedia Fóundation, Inc., a nón-profit organization.
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