countregFitModel - What model selection methods are available in the countregFitModel action?

Model selection can be performed using the 'selection' parameter. The available methods ('method') include 'FORWARD', 'BACKWARD', 'STEPWISE', 'LASSO', and 'ELASTICNET'. You can control the selection process with criteria such as 'AIC', 'SBC', or significance levels ('slEntry', 'slStay').