Hi. I have data which i would want to assess the degree of agreement between two assays, e.g., to evaluate reproducibility or for inter-rater reliability. I have used the Pearson product-moment correlation coefficient. It looks good ranginging between 0.90 to 0.998. Though this looks good. I am told the Concordance correlation coefficient will give a better picture of how reproducible the assay is. Does any one know how to run such a test using R? If so can you kindly provide the code, and bit of explanations to spruce it up? Thank you Paul
concordance correlation coefficient using R
3 messages · paul murima, Bruno Falissard, Marc Schwartz
You can look at the fonction icc in the package psy. Best regards, Bruno ---------------------------------------------------------------------------- Bruno Falissard INSERM U669, PSIGIAM "Paris Sud Innovation Group in Adolescent Mental Health" Maison de Solenn 97 Boulevard de Port Royal 75679?Paris cedex 14, France tel : (+33) 6 81 82 70 76 fax : (+33) 1 58 41 28 43 web?site : http://perso.wanadoo.fr/bruno.falissard/ ---------------------------------------------------------------------------- -----Message d'origine----- De?: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] De la part de paul murima Envoy??: dimanche 7 d?cembre 2008 16:23 ??: r-help at r-project.org; r-help at stat.math.ethz.ch Objet?: [R] concordance correlation coefficient using R Hi. I have data which i would want to assess the degree of agreement between two assays, e.g., to evaluate reproducibility or for inter-rater reliability. I have used the Pearson product-moment correlation coefficient. It looks good ranginging between 0.90 to 0.998. Though this looks good. I am told the Concordance correlation coefficient will give a better picture of how reproducible the assay is. Does any one know how to run such a test using R? If so can you kindly provide the code, and bit of explanations to spruce it up? Thank you Paul ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
on 12/07/2008 09:23 AM paul murima wrote:
Hi. I have data which i would want to assess the degree of agreement between two assays, e.g., to evaluate reproducibility or for inter-rater reliability. I have used the Pearson product-moment correlation coefficient. It looks good ranginging between 0.90 to 0.998. Though this looks good. I am told the Concordance correlation coefficient will give a better picture of how reproducible the assay is. Does any one know how to run such a test using R? If so can you kindly provide the code, and bit of explanations to spruce it up? Thank you Paul
Look at the epi.ccc function in the epiR CRAN package. More information here: http://bm2.genes.nig.ac.jp/RGM2/R_current/library/epiR/man/epi.ccc.html You might also want to review Martin Bland's page pertaining to the design and analysis of measurement agreement studies: http://www-users.york.ac.uk/~mb55/meas/meas.htm HTH, Marc Schwartz