I was wondering if you could clarify whether the model was cross-validated or just fitted to the entire dataset? Also, regarding the reported R-squared (R²) value—was that based on out-of-fold (OOF) data, or from the fitted model? I ask because R² from the fitted model might overstate how well the model actually performs.

Additionally, I noticed that metrics like RMSE, MSE, or MAE weren’t reported. These metrics might offer a better sense of the model's error magnitude and how it truly performs. Any chance you could share why those weren’t included?