When working with [[Association Rules|association rules]], the leverage [[Error Metrics|metric]] computes the difference between the observed frequency of an antecedent set and consequent set appearing together and the frequency that would be expected if they were independent. It is derived from the [[Support of an Item Set|support]] as: $ \text{leverage}(A \rightarrow C) = \text{support}(A \rightarrow C) - \text{support}(A) \times \text{support}(C) $ It lies in the $[-1,1]$ interval and a leverage value of 0 indicates independence.