1. A computer implemented method for classifying a document comprising the steps of: providing a single lexicon comprising one or more lexicon terms wherein the one or more lexicon terms are associated with category information, and wherein the category information comprises weights indicating a likelihood that each of the one or more lexicon terms corresponds to each of one or more categories, identifying a document comprising one or more document terms, comparing the one or more document terms with the one or more lexicon terms, determining which, if any, of the one or more document terms match the one or more lexicon terms, calculating a score indicating a likelihood that the document belongs to each of the one or more categories using the weights for each of the matched terms, outputting a result of the calculating step, and calculating additional moments based upon relative distances of subsequent terms matched with additional terms whose moment meets the requirements of the threshold.