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. 2015 Apr 2;10(3):e0121945.
doi: 10.1371/journal.pone.0121945. eCollection 2015.

cocor: a comprehensive solution for the statistical comparison of correlations

Birk Diedenhofen  1 , Jochen Musch  1
Affiliations

cocor: a comprehensive solution for the statistical comparison of correlations

Birk Diedenhofen et al. PLoS One. .

Erratum in

Abstract

A valid comparison of the magnitude of two correlations requires researchers to directly contrast the correlations using an appropriate statistical test. In many popular statistics packages, however, tests for the significance of the difference between correlations are missing. To close this gap, we introduce cocor, a free software package for the R programming language. The cocor package covers a broad range of tests including the comparisons of independent and dependent correlations with either overlapping or nonoverlapping variables. The package also includes an implementation of Zou's confidence interval for all of these comparisons. The platform independent cocor package enhances the R statistical computing environment and is available for scripting. Two different graphical user interfaces-a plugin for RKWard and a web interface-make cocor a convenient and user-friendly tool.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. A flowchart of how to use the four main functions of cocor, displaying all available tests.
For each case, an example of the formula passed as an argument to the cocor() function and the required correlation coefficients for the functions cocor.indep.groups(), cocor.dep.groups.overlap(), and cocor.dep.groups.nonoverlap() are given. The test label before the colon may be passed as a function argument to calculate specific tests only.
Fig 2
Fig 2. Screenshot of the cocor GUI plugin for RKWard.
Fig 3
Fig 3. Screenshot of the cocor web interface on http://comparingcorrelations.org.
See this image and copyright information in PMC

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