The predicted residual error sum of squares (PRESS) is a type of cross-validation used to evaluate the predictive ability of a regression model. Predicted r-square is a related goodness-of-fit measure. This add-in will calculate the predicted r-square from the PRESS and the total sum of squares (SST) and place it in a column next to PRESS in the report window when using Fit Model. Please note, Analysis of Variance and Press must be turned on in the report window prior to running this add-in. If needed, turn them on by selecting *Regression Report > Analysis of Variance* and *Row Diagnostics > Press* from the red triangle menu next to the response.