Introduction | Install and load required packages | Import and explore the data | Prepare the longitudinal data | Phase 1: Fit the Longitudinal GRMTree | Phase 2: Characterize response shift | Accessing the results | Visualizing response shift | Extracting parameters and scores | Interpreting a tree with no split | Conclusion | References

Introduction | Install and Load required packages | Import and explore the data | IRT Assumptions: Check for unidimensionality assumption | Fit the graded response model (GRM) | Fit Indices for the GRM | Visualization: Visualize the results for all the items | Fit the tree-based graded response model (GRMTree) | Print the tree | Plot the GRMTree | Extract item parameters for terminal nodes | Conclusion

Introduction | Install and Load required packages | Import and prepare the data | GRM Forests Implementation | Define the forest control parameters | Grow the GRM Forest | Variable Importance | Compute the variable importance of each covariate | Plot the variable importance of each variable | Conclusion