This site presents extra materials related to the paper A Multidimensional Zero-Inflated Graded Response Model for Ordinal Symptom Data, which is now under review The **Paper** folder contains the manuscript pre-print and online supplemental materials The **Data Analysis** folder contains the data set and R code used in the paper - CompleteData3000.csv: comma separate data file. Complete data from the PHQ-9 scale from 3000 participants - GRM.R: R code for the unidimensional Graded Response model - TestInflation.R: R code for the GRM model with test inflation parameter - ItemInflation.R: R code for the GRM model with item inflation parameters - ItemInflationOneLV.R: R code for the GRM model with 2PL IRT model accounting for item inflation. Both GRM and 2PL are models share the same latent factor - ItemInflationTwoLV.R: R code for the GRM model with 2PL IRT model accounting for item inflation. GRM and 2PL are models are define with separate (correlated) latent factors The **Posterior Predictive Checks** (PPC) folder includes plots for the PPC for the models that are not included in the paper - PPC_GRM: PPC plots for the unidimensional Graded response model - PPP_MIRT: PPC plots for the two dimensional Graded response model - PPC_Test: PPC plots for the GRM model with test inflation parameter - PPC_IZI: PPC plots for the GRM model with item inflation parameters - PPC_OneLV: PPC plost for the GRM model with 2PL IRT model accounting for item inflation. Both GRM and 2PL are models share the same latent factor