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hello, I estimated an IRT model on 14 items measured on a 5point likert scale using MLR. M+ indicates that THE CHISQUARE TEST IS NOT COMPUTED BECAUSE THE FREQUENCY TABLE FOR THE LATENT CLASS INDICATOR MODEL PART IS TOO LARGE. However, other programs do compute chisquare for this model. Is there a way to bypass this problem and obtain chisquares? Another problem: I estimate several different models. In each of these models, there are 8 items on a 5point scale. The degree of freedom for each chisquare differ because M+ delete a certain number of "cells in the latent class indicator table" "due to extreme value". Could you please indicate a reference that justifies this deletion? Thank you in advance for your help. 


When the frequency table for chisquare is very large as in your situation, there are too many cells ( 5*5*5*etc.) to make the test meaningful. We don't recommend using it with over 8 binary indicators. I think you can find a discussion of this in the Agresti book. 


thank you for your prompt answer. I would just like to ask some precisions. I know that the frequency table for a questionnaire with 14 questions and 5 modalities per question is 5^14. However, is there another goodness of fit statistic, given by Mplus, that could help to estimate if the model fits (i.e. absolute fit and not relative fit like AIC)? Second question: concerning the deletion of extreme value, I wish to publish examining several 8 items scales. The degrees of freedom should be the same. However, since the deletion is not always the same, the df differ. I am sure that the reviewers will ask why and I would like to cite a reference explaining the deletion and thus the difference in df. thank you. 


I would look at the bivariate standardized residuals in TECH10. You may find what you want in the Agresti book regarding deleted cells. 

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