Goodman–Kruskal’s gamma
a measure of association between two categorical variables, where 0 represents no relationship and 1 represents perfect association. For example, a marketing researcher may want to assess the relationship between the location of a store and the type of clothes purchased. A Goodman–Kruskal’s gamma of .30 or higher would indicate a medium-sized correlation, such that clothes distributors desiring to maximize sales should provide specific kinds of clothes at specific locations. Also called Goodman–Kruskal’s tau. [Leo A. Goodman (1928– ) and William Henry Kruskal (1919–2005), U.S. statisticians]