This psychosocial role-theoretical approach to personality attempts to combine the conceptual utility of a role-theoretical perspective with the methodological utility of modern psychometric theory and multivariate research design. It focuses on the prediction of situation-specific interpersonal behavior. A conceptual model is presented, as well as measurement and research models for operationalizing it. Research studies are described which tested the empirical validity of the conceptual model and illustrated the application of the measurement and research models. Each study was concerned with the development and cross-validation of a set of measures for predicting situation-specific behavior. The different types of role-related behavior utilized were: (1) a traditional performance variable, academic achievement; (2) self-reported behavior; and (3) behavior observed in an experimentally controlled situation. Results supported the validity of the conceptual model. As predicted by the model, both person and situation variables were differentially and significantly related to the various indices of role performance. Results of the cross-validation of each study indicated that better prediction of situation-specific behavior can be obtained by combining both sources of information. (Author)