A latent state-trait model for analyzing states, traits, situations, method effects, and their interactions

ObjectiveStudies on situation and PersonxSituation interaction effects often use only one method of measurement, so that the extent to which the effects may be method-specific cannot be determined. We introduce a new multimethod latent state-trait model for random and fixed situations (MM-LST-RF), which allows examining person, situation, and PersonxSituation interaction effects in the context of multimethod measurement designs (e.g., studies with multiple reporters), and discuss potential areas of application for the new model in personality research. MethodThe new model allows analyzing novel features of multimethod, multi-situation data, including (a) the convergent validity and method specificity of trait (person) effects, situation effects, and PersonxSituation interaction effects; (b) the degree of situation specificity of method effects; and (c) potential MethodxSituation interactions. An application to smoker's affect (N=235; 57% female; 93% Caucasian) before and after quitting smoking is presented with positively and negatively worded items as methods. ResultsThe MM-LST-RF model fit the smoking data well. Method specificity of many effects was high. ConclusionsThe MM-LST-RF model provides researchers with a new framework for testing method specificity of person, situation, and interaction effects.