As mentioned, we need more details to help answer this question.  As a best practice, I want to point you to a paper that hits on several data mining topics.  It is several years old, but it is a fantastic paper to help in optimizing your data mining analysis.  It is called Identifying and Overcoming Common Data Mining Mistakes.  It is found at the following URL:    https://support.sas.com/resources/papers/proceedings/proceedings/forum2007/073-2007.pdf ... View more