The integrated theory (IT) is constructed on the basis of a candidate set. Initially this set contains all the rules of the individual theories T1..Tn. The objective is to select some rules from the candidate set and transfer them into IT so as to achieve good performance (accuracy). The method relies on the qualitative and quantitative characterization of rules and includes the following steps :
(1) Order rules in the candidate set according to rule quality.
(2) Select the rule R with the best quality and include it in IT.
(3) Mark the cases covered by R.
(4) Recalculate the quality estimates of rules excluding the marked cases.
(5) Go back to (1).
The process of adding new rules to IT terminates when the accuracy of the 'best rule' in the candidate set falls below a certain threshold.
It can be seen that some kind of forgetting is performed via knowledge integration, because some learned rules are thrown away as a consequence of the evaluation process. Nevertheless, the performance gets better.