A method for classifying a document using identified patterns includes determining frequent patterns based on a group of resources, where the frequent patterns include sets of words associated with resources that are related to a particular topic; determining frequent anti-patterns based on another group of resources, where the frequent anti-patterns include sets of words associated with resources that are not related to the particular topic, where the second group of resources is different from the first group of resources; determining a probability that the document is related to the particular topic based on the frequent patterns and the frequent anti-patterns; and determining a topic classification of the document based on the determined probability.