Tree-based construction of low-cost action rules

A rule as actionable, if a user can do an action to his/her advantage based on that rule. Actionability can be expressed in terms of attributes that are present in a database. Action rules are constructed from certain pairs of classification rules previously extracted from the same decision table. Each such classification rule defines a preferable decision class. Attributes in a decision table are divided into two groups: stable and flexible. Flexible attributes provide a tool for making hints to a user to what changes within some values of flexible attributes are needed to reclassify a group of objects, supporting the action rule, from one decision class to another, more desirable, one. Changes of values of some flexible attributes can be more expensive than changes of other values. The notion of a cost can be introduced and assigned by an expert to each such a change.