Concordance correlation coefficient
| Command: | Statistics Agreement & responsivenessConcordance correlation coefficient |
Description
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.
Results
The concordance correlation coefficient ρc contains a measurement of precision ρ and accuracy Cb:
where
- 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.
Descriptive scale
McBride (2005) suggests the following descriptive scale for values of the concordance correlation coefficient (for continuous variables):
| Value of ρc | Strength of agreement |
|---|---|
| < 0.90 | Poor |
| 0.90 - 0.95 | Moderate |
| 0.95 - 0.99 | Substantial |
| >0.99 | Almost perfect |
Literature
- Lin L.I-K (1989) A concordance correlation coefficient to evaluate reproducibility. Biometrics 45:255-268.
- 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)