Since the goal of the traditional direct marketing model is to identify customers who are most likely to respond to the promotion, it follows that the effectiveness of such a model, or campaign, is determined by the response rate of contacted customers. This evaluation criterion has long been adopted by numerous works in both academic and commercial settings [LL98, KDD98, Bha00, PKP02, DR94]. Intuitively, it seems that the more responders that exist among those contacted customers, the better — in other words, as long as a contacted customer responds, it is considered to be a positive result. However,.
