Concordance correlation coefficient

Command:

Statistics Method comparison 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:

ρ_c = ρ C_b

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
• C_b 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.

Literature

• Lin L.I-K (1989) A concordance correlation coefficient to evaluate reproducibility. Biometrics 45:255-268. [Abstract]
• Lin L.I-K (2000) A note on the concordance correlation coefficient. Biometrics 56:324-325.

See also

• Intraclass correlation coefficient
  
• Inter-rater agreement (kappa)