Skip to main content
Mail a PDF copy of this page to:
(Your email address will not be added to a mailing list)
Show menu Show menu

Concordance correlation coefficient


The concordance correlation coefficient (Lin, 1989) evaluates the degree to which pairs of observations fall on the 45° line through the origin.

Required input

Select the variables for the two techniques you want to compare.

Concordance correlation coefficient - dialog box


The concordance correlation coefficient ρc contains a measurement of precision ρ and accuracy Cb:

Concordance correlation coefficient formula$$\rho_c = \rho \space C_b$$


  • ρ is the Pearson correlation coefficient, which measures how far each observation deviates from the best-fit line, and is a measure of precision, and
  • Cb is a bias correction factor that measures how far the best-fit line deviates from the 45° line through the origin, and is a measure of accuracy.

Concordance correlation coefficient - results

Descriptive scale

McBride (2005) suggests the following descriptive scale for values of the concordance correlation coefficient (for continuous variables):

Value of ρcStrength of agreement
< 0.90Poor
0.90 - 0.95Moderate
0.95 - 0.99Substantial
>0.99Almost perfect


  • Lin L.I-K (1989) A concordance correlation coefficient to evaluate reproducibility. Biometrics 45:255-268. PubMed
  • Lin L.I-K (2000) A note on the concordance correlation coefficient. Biometrics 56:324-325.
  • McBride GB (2005) A proposal for strength-of-agreement criteria for Lin's Concordance Correlation Coefficient. NIWA Client Report: HAM2005-062. (PDF)

See also

External links