This dissertation investigated the use of various techniques in modeling non-linear change in the context of latent growth modeling. A simulation study was conducted utilizing four between subjects factors: sample size (50, 75, 100, 150, 200, 300 and 500), slope variance (.15, .45 and .75),...

Assessing IRT model-fit and comparing different IRT models from a Bayesian perspective is gaining attention. This research evaluated the performance of Bayesian model-fit and model-comparison techniques in assessing the fit of unidimensional Graded Response (GR) models and comparing different GR...

One of the sources of inaccuracy in parameter estimates of multilevel models is omitted variable bias, caused by the omission of an important predictor. The purpose of this study was to examine the performance of six estimation procedures in estimating the fixed effects when a level-2...

The purpose of this study was to investigate the performance of Beaton~{!/~}s MR and MSR fit indices for assessing goodness-of-fit of IRT models. These statistics are based on a standardized residual calculated from an expected and observed response. The investigation was conducted using a Monte...

This study evaluated the robustness of DIF detection for multidimensional polytomous items using two different estimation methods, MG-CFA and MGRM-DFIT. A simulation study across 960 study conditions was performed. The purpose of this study was to establish the Type-I error rate and Power of DIF...