Testing the Difference between Dependent Correlations Using the Fisher Z

Abstract

Several proposed statistics for testing the significance of the difference in two correlated r’s were first reviewed. A simple alternate procedure based on the familiar Fisher z was then suggested. This procedure, unlike its predecessors, is applicable to a wide range of problems involving tests between dependent correlations. It also has documented mathematical support when its power curves are examined. Since the procedure is asymptotic, a large sample size is required. The only other assumption is that the observations associated with the sample are drawn from a joint multivariate normal distribution.