MTO Research Sandwich Tuesday, February 16 PZ 43 at 12:45h 12:45h dr. Duygu Güngör Culha (Dept. Methodology & Statistics, Tilburg University and Faculty of Art and Sciences, Department of Psychology Izmir University). ‘Detecting Measurement Equivalence with Latent Markov Models’ Measurement equivalence in longitudinal studies guarantees that the same measurement instrument used in different time points measures exactly the same construct. Some example studies with different latent variable models include item response theory and latent growth models. However, testing measurement equivalence with latent Markov models seems to be neglected; many applications of latent Markov models assume measurement equivalence or give little attention to this topic. When testing for inequivalent items with nested models approach there are different alternative strategies. One question to be answered is which data analytic technic should be used for the detection of equivalence. In this talk, I will focus on free baseline and constrained baseline strategies. When the baseline model is free model, we estimate a model where all item response probabilities for all time points are free to vary. The next step is to specify a series of models with one item restricted. On the other hand, baseline model can be constrained model that all items are assumed equivalent. Then, one can free items one-by-one to flag nonequivalent items. In this simulation study, we explore overall performance of latent Markov models in testing measurement equivalence using free baseline and constrained baseline models. Our simulation conditions are related to sample size, measurement strength, amount of inequivalence, number of inequivalent items, and statistics used for model selection.