The Role of Measurement Quality on Practical Guidelines for Assessing Measurement and Structural Invariance.

Although differences in goodness-of-fit indices (ΔGOFs) have been advocated for assessing measurement invariance, studies that advanced recommended differential cutoffs for adjudicating invariance actually utilized a very limited range of values representing the quality of indicator variables (i.e., magnitude of loadings). Because quality of measurement has been found to be relevant in the context of assessing data-model fit in single-group models, this study used simulation and population analysis methods to examine the extent to which quality of measurement affects ΔGOFs for tests of invariance in multiple group models. Results show that ΔMcDonald's NCI is minimally affected by loading magnitude and sample size when testing invariance in the measurement model, while differences in comparative fit index varies widely when testing both measurement and structural variance as measurement quality changes, making it difficult to pinpoint a common value that suggests reasonable invariance.