1. A method for modeling an information request, comprising: receiving unlabeled and labeled documents; extracting a set of features from each document; learning a model from example documents marked as positive or negative with respect to said request wherein said model scores documents to evaluate a degree of membership in a group responsive to said request; evaluating the performance of model settings on example documents; applying an adjustment algorithm that provides a threshold value θ new ; applying a scoring function that computes score, a value assigned to a document by the learnt model, and classifies the document based on the sign of the following equation: 
 Class( X )=Sign(score−θ new )