Computer programs for the concordance correlation coefficient.
The CCC macro is presented for computation of the concordance correlation coefficient (CCC), a common measure of reproducibility. The macro has been produced in both SAS and R, and a detailed presentation of the macro input and output for the SAS program is included. The macro provides estimation of three versions of the CCC, as presented by Lin [L.I.-K. Lin, A concordance correlation coefficient to evaluate reproducibility, Biometrics 45 (1989) 255-268], Barnhart et al. [H.X. Barnhart, J.L. Haber, J.L. Song, Overall concordance correlation coefficient for evaluating agreement among multiple observers, Biometrics 58 (2002) 1020-1027], and Williamson et al. [J.M. Williamson, S.B. Crawford, H.M. Lin, Resampling dependent concordance correlation coefficients, J. Biopharm. Stat. 17 (2007) 685-696]. It also provides bootstrap confidence intervals for the CCC, as well as for the difference in CCCs for both independent and dependent samples. The macro is designed for balanced data only. Detailed explanation of the involved computations and macro variable definitions are provided in the text. Two biomedical examples are included to illustrate that the macro can be easily implemented.
Crawford
Sara B
SB
Division of Parasitic Diseases, Centers for Disease Control and Prevention, 4770 Buford Highway NE (MS-F22), Atlanta, GA 30341, United States. sgv0@cdc.gov
Kosinski
Andrzej S
AS
Lin
Hung-Mo
HM
Williamson
John M
JM
Barnhart
Huiman X
HX
D016893:Carotid Stenosis / Q000175:diagnosis; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D006801:Humans; D018810:Magnetic Resonance Angiography; D008954:Models, Biological; D015203:Reproducibility of Results; D012984:Software; D013223:Statistics as Topic