Abstract: Techniques for optimizing decision making apparatus by instrumenting the apparatus and running it on test data which has the characteristics of the data upon which the decision making apparatus is to be used. The information provided by the instruments is then used to reorder the application of the criteria used by the decision making apparatus to the data. The techniques are applied in rule-based system which employs a decision network to evaluate the rules. The decision network is instrumented and the rule-based system is run on the test data. The results returned by the instrumentation are used to determine how to rearrange condition elements in the rules so that the flow of data through the decision network is minimized. The condition elements are then rearranged in that fashion and the modified rule-based system is employed on real data.