MEASUREMENT EQUIVALENCE OF WATSON AND CLARKS 18 SURROGATE MEASURES OFNEGATIVE AFFECTIVITY - APPLYING THE PRINCIPLE OF TETRAD DIFFERENCES TO AN INCOMPLETE CORRELATION MATRIX

Watson and Clark concluded, based primarily on a subjective analysis o f the positive manifold of 87 intercorrelations, that 18 personality m easures were manifestations of the same stable and pervasive trait of negative affectivity. Confirmatory factor analysis to test a one-facto r measurement model was not possible, since only an incomplete matrix of correlations (87 out of 153) was available. In this paper, the prin ciple of tetrad differences was applied to an incomplete correlation m atrix to test for a general factor across the 18 measures. This princi ple assesses the equivalence of different measures hypothesized to tap into the same construct. Of the 614 first-order partial correlations, only 44 (7.2 %) failed to satisfy the principle of tetrad differences , indicating support for a common underlying trait. In addition, confi rmatory factor analysis and Herman's one-factor test provided support for a general factor across a subset of the 18 scales for which a comp lete matrix of correlations was available.