A longitudinal multilevel CFA-MTMM model for interchangeable and structurally different methods

One of the key interests in the social sciences is the investigation of change and stability of a given attribute. Although numerous models have been proposed in the past for analyzing longitudinal data including multilevel and/or latent variable modeling approaches, only few modeling approaches have been developed for studying the construct validity in longitudinal multitrait-multimethod(MTMM) measurement designs. The aim of the present study was to extend the spectrum of current longitudinal modeling approaches for MTMM analysis. Specifically, a new longitudinal multilevel CFA-MTMM model for measurement designs. The aim of the present study was to extend the spectrum of current longtudinal modeling approaches for MTMM analysis. Specifically, a new longituinal multilevel CFA-MTMM model for measurment designs with structurally different and interchangeable latent-State-Combination-Of-Methods model, LS-COM) is presented. Interchangable methods are methods that are randomly sampled from a set of equivalent methods(e.g., multiple student ratings for teaching qualityy, whereas structuarlly different methods are methods that cannot be easily replaced by one another (e.g., teacher, self-ratings, princple ratings). results of a simualtion study indicate that the parameters and standard errors in the LS-COM model are well recovered even in conditionms with only fve observations per estimated model paramete. The advantages and limitations of the LS-COM model relative to other longitudinal MTMM modelling approches are discussed.