Accuracy, reliability, and timing of visual evaluations of decay in fresh-cut lettuce
Fig 2
Examples of indexes used for evaluations of agreement between pairs of ratings.
Pearson correlation coefficient (r) provides good information about the closeness of the ratings to the best-fitting line (best fitting line is in orange). Lin’s concordance coefficient (ρc) combines both the closeness of the ratings to the best-fitting line and how the best-fitting line conforms to the identity line. Identity line (also called line of equality, 1:1 line, or x = y line) leads from the origin at 45-degrees (slope of 1) and represents the perfect agreement between evaluations (identity line is in dashed black). Coefficient of bias (Cb) represents the ratio between the concordance coefficient and the correlation coefficient Cb = ρc /r. Upper row shows pairs of ratings with perfect correlation coefficient, but imperfect concordance coefficient. Lower row shows pairs of ratings with coefficient of bias = 1, but imperfect concordance coefficient.