 The Sørensen index equals twice the number of elements common to both sets divided by the sum of the number of elements in each set.When applied to Boolean data, using the definition of true positive (TP), false positive (FP), and false negative (FN), it can be written as

It is different from the Jaccard index which only counts true positives once in both the numerator and denominator.DSC is the quotient of similarity and ranges between 0 and 1.