Concordance correlation coefficient
Command: 
Statistics Agreement & responsiveness Concordance 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 ρ_{c} contains a measurement of precision ρ and accuracy C_{b}:
where
 ρ is the Pearson correlation coefficient, which measures how far each observation deviates from the bestfit line, and is a measure of precision, and
 C_{b} is a bias correction factor that measures how far the bestfit 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 ρ_{c}  Strength of agreement 
< 0.90  Poor 
0.90  0.95  Moderate 
0.95  0.99  Substantial 
>0.99  Almost perfect 
Literature
 Lin L.IK (1989) A concordance correlation coefficient to evaluate reproducibility. Biometrics 45:255268. [Abstract]
 Lin L.IK (2000) A note on the concordance correlation coefficient. Biometrics 56:324325.
 McBride GB (2005) A proposal for strengthofagreement criteria for Lin's Concordance Correlation Coefficient. NIWA Client Report: HAM2005062. (PDF)
See also
External links
