So, you may ask, are all of the patterns interesting? Typically not – only a small fraction of the patterns potentially generated would actually be of interest to any given user.

This raises some serious questions for data mining. You may wonder, What makes a pattern interesting? Can a data mining system generate all of the interesting patterns? Can a data mining system generate only interesting patterns?

To answer a first question, a pattern is interesting, if (1) it is easily understood by humans, (2) valid on new or test data with some degree of certainty, (3) potentially useful and (4) novel. A pattern is also interesting if it validates a hypothesis that the user sought to confirm. An interesting pattern represents knowledge.