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The radial plot in meta-analysis : approximations and applications

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Copas, John B. and Lozada-Can, Claudia. (2009) The radial plot in meta-analysis : approximations and applications. Journal of the Royal Statistical Society Series C: Applied Statistics, Vol.58 (No.3). pp. 329-344. ISSN 0035-9254

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Official URL: http://dx.doi.org/10.1111/j.1467-9876.2008.00650.x

Abstract

Fixed effects meta-analysis can be thought of as least squares analysis of the radial plot, the plot of standardized treatment effect against precision (reciprocal of the standard deviation) for the studies in a systematic review. For example, the least squares slope through the origin estimates the treatment effect, and a widely used test for publication bias is equivalent to testing the significance of the regression intercept. However, the usual theory assumes that the within-study variances are known, whereas in practice they are estimated. This leads to extra variability in the points of the radial plot which can lead to a marked distortion in inferences that are derived from these regression calculations. This is illustrated by a clinical trials example from the Cochrane database. We derive approximations to the sampling properties of the radial plot and suggest bias corrections to some of the commonly used methods of meta-analysis. A simulation study suggests that these bias corrections are effective in controlling levels of significance of tests and coverage of confidence intervals.

Item Type:	Journal Article
Subjects:	Q Science > QA Mathematics R Medicine > R Medicine (General)
Divisions:	Faculty of Science > Statistics
Library of Congress Subject Headings (LCSH):	Meta-analysis, Systematic reviews (Medical research)
Journal or Publication Title:	Journal of the Royal Statistical Society Series C: Applied Statistics
Publisher:	Wiley-Blackwell Publishing, Inc
ISSN:	0035-9254
Date:	July 2009
Volume:	Vol.58
Number:	No.3
Number of Pages:	16
Page Range:	pp. 329-344
Identification Number:	10.1111/j.1467-9876.2008.00650.x
Status:	Not Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Open Access
Funder:	Consejo Nacional de Ciencia y Tecnología (Mexico) [Mexican Council for Science and Technology] (CONACYT)
Grant number:	160859 (CONACYT)
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URI:	http://wrap.warwick.ac.uk/id/eprint/27892