Evidence for the Type in Type A Behavior: A Taxometric Analysis

Four taxometric procedures were applied to the self-report responses of 1,239 Ss who completed the Jenkins Activity Survey (JAS). All 4 procedures provided clear evidence for a latent class variable. A continuous model simulation that mimicked the item characteristics of the JAS correctly rejected the presence of a latent class variable. Using an external validation procedure, I reexamined 5 previously published studies to determine if the simple Type A-B dichotomy was as predictive of outcome measures as the use of continuous JAS scores. The presence of a latent class variable predicts no gain in predictive power in moving from a simple dichotomy to continuous scores. Across 5 studies, there was a slight decrease in the size of the relation between Type A-B and outcome for the continuous JAS scores relative to the simple Type A-B dichotomy. Taken together, these results suggest that the Type A-B distinction is based on a latent typology.