Degree of Freedom Values

Click the DF of covariates button on the GAM Specifications dialog box - Quick tab to display the Degree of freedom values dialog box, which is used to specify the degrees of freedom for the cubic spline smoother that will be applied to each predictor variable. The fewer degrees of freedom you specify, the smoother is the cubic spline fit to the partial residuals, and typically, the worse is the overall fit of the model. The issue of degrees of freedom for smoothers is discussed in detail in Hastie and Tibshirani (1990).

OK
Click the OK button to accept the values entered and return to the GAM Specifications - Quick tab.
Cancel
Click the Cancel button to return to the GAM Specifications dialog box - Quick tab, disregarding any changes you have made in this dialog box.
Common Value
Enter in the Common Value box a common value to use for the degrees of freedom for the cubic spline smoother that will be applied to all of the predictor variables.
Apply
Click the Apply button to apply the value specified in the Common Value group box to all of the predictor variables.