The propensity score method is frequently used to deal with bias from standard regression in observational studies. The propensity score method involves calculating the conditional probability (propensity) of being in the treated group (of the exposure) given a set of covariates, weighting (or sampling) the data based on these propensity scores, and then analyzing the outcome using the weighted...

The impor tance of good weighting methods in information retrieval methods tha t stress the most useful features of a document or query representat ive is examined. Evidence is presented tha t good weighting methods are more impor tan t than the feature selection process and it is suggested tha t the two need to go handin-hand in order to be effective. The paper concludes with a me thod for lea...