Latent State-Trait Modeling: A New Tool to Refine Temperament Methodology.

Questions concerning longitudinal stability and multi-method consistency are critical to temperament research. Latent State-Trait (LST) analyses address these directly, and were utilized in this study. Thus, our primary objective was to apply LST analyses in a temperament context, using longitudinal and multi-method data to determine the amount of trait vs. state variance, as well as convergence for measures of Distress to Limitations (DL) facets. Mothers' ratings and independent observations of DL behaviors collected on two occasions (8 months old and 12 months old) for 148 infants (49.2% female) were utilized. Single source latent state-trait (LST) analyses indicated that parent ratings of DL behavior (PDL) contained more trait (M = 61%) than state residual (M = 39%) variance, whereas independent observations (IO) of DL behavior contained substantially more state residual (75%) than trait (25%) variance. A multiple source LST analysis indicated virtually zero convergence for either trait or state residual variance between PDL and IO ratings (M = 2%). In conclusion, PDL ratings were more trait-like across the four-month interval, whereas IO ratings of DL were more state-like in nature. Also, no convergence was found between the two methods of measurement. Results are discussed with an emphasis on implications for the utility of LST analyses in temperament research.