A Measure Of Similarity Between Individuals When Scoring Directions Of Variables Are Arbitrary.

Holley and Guilford have proposed an index, G, originally intended for use in Q type factor analysis when scoring directions are arbitrary. G is appropriate for dichotomous data only. In this paper, a general measure is derived which is identical to G in the case of dichotomous data. The measure is approximately equal to the mean inter-person covariance when all permutations of scoring directions are considered. The measure is also closely connected both with component analysis of individual differences and with the condition of proportionality between two sets of observed values.