The Unified Approach for Model Evaluation in Structural Equation Modeling

ii Practical fit indices have been widely used for model fit evaluation in Structural Equa-tion Modeling. This dissertation discusses the properties of the fit indices including their influencing factors. These properties prevent researchers from deriving one-size-fit-all cutoffs for the fit indices. In addition, the past simulation studies on model fit evaluation have several limitations. The major limitation is that most studies have fo-cused on test of exact fit rather than approximate fit which is not consistent with the goal of practical fit indices. This dissertation reviews alternative approaches to account for the limitations and proposes a unified method for model fit evaluation combining the advantages of the alternative approaches. The unified approach allows researchers to test approximate fit and take into account sampling error in model evaluation. Two simulation studies are conducted to investigate the performance of the unified approach comparing to the other model fit evaluation methods. Two types of mod-els are included in this study: confirmatory factor analysis and growth curve models