Downscaling with benefits: A road forward for capturing intra-individual variations in personality

The measurement of personality traits is well established, but the measurement of personality states is still evolving. Typically, trait questionnaires are adapted for state measurement by adding temporal references like “today.” This approach assumes that traits and states share the same measurement model, conflicting with findings that within-personality structures differ between individuals. We offer an attempt to identify the facets of personality states which are structured as similar as possible for different individuals using multilevel exploratory and multilevel confirmatory factor analyses. Thereby we want to be able to measure these aspects of personality validly within and between persons at the same time. In an intensive longitudinal daily diary study, we used multilevel exploratory factor analyses in Sample 1 (4976 diaries, 73 participants) to identify item sets with consistent factor loadings both within and between individuals. We then examined these instruments' model fit in Sample 2 (5123 diaries, 71 participants) using multilevel confirmatory factor analyses. Results indicated that within-person factor structures differ among individuals. Nonetheless, we identified facets with comparable within- and between-person structures of personality states that we labeled as Vulnerability to Stress, Sociability, Nonantagonistic Orientation, Achievement or Dependability. We seek to encourage advancements towards more sophisticated personality state measures.