is about is_proxy_for has numerator has denominator correlation coefficient standard deviation covariance Matthews correlation coefficient 2 Philippe Rocca-Serra adapted from wikipedia: https://en.wikipedia.org/wiki/Matthews_correlation_coefficient and from: https://doi.org/10.1016/0005-2795(75)90109-9 MCC phi coefficient Matthews Correlation Coefficient (or MCC) is a correlation coefficient which is a measure of the quality of binary (two-class) classifications, introduced by biochemist Brian W. Matthews in 1975. mcc(preds = NULL, actuals = NULL, TP = NULL, FP = NULL, TN = NULL, FN = NULL) from: https://www.rdocumentation.org/packages/mltools/versions/0.3.4/topics/mcc measure of association ratio-based measure of association ready for release