design IRT embodies a view of induction as a four-phase process (shown in Figure 1). The process alters a current model by generating a group of new competitor models, fitting those competitor models to data, comparing the competitors to each other, and then testing the statistical significance of the competitors. The process is iterative --- it can be repeated until no competitor can be found that is significantly better than the current model. current model generate competitors fit competitors compare competitors test significance Replace current model with competitor any competitor significantly better? No Yes continue searching? accept current model No Yes Figure 1: IRT's inductive process Generating competitors creates one or more models with a different structure than the current model. Examples include creating decision trees with different attributes and structure or classification rules with different conditions and operators. Each of these competitors is a candidate to replac...