SI-CHAID is a program for performing CHAID (CHi-squared Automatic Interaction Detector) analyses. Results can be displayed simultaneously in the form of an intuitive tree diagram, crosstabulations, and a gains chart summary. The Define part of the program is used to set up a CHAID Definition (.chd) file with the File → New command, or alter the specifications of an existing .chd file with File → Open. The typical setup includes the selection of the dependent variable, the predictor variables, the combine-type of the predictors, and various options for growing the tree (stopping rule, significance levels, etc.). Define may also be used to enter or modify scores for the categories of the dependent variable when the ordinal algorithm is specified. The model specifications, which are saved with a .chd extension, can be inspected with a text editor (Notepad, for example).