Some embodiments provide a program that identifies an entity having an entity attribute. The program receives, from each method of several methods, a set of candidate identity attributes that are each for identifying a particular entity having the entity attribute specified in the document. Each method of the several methods generates the corresponding set of candidate identity attributes based on the entity attribute specified in a document. The program calculates a score for each candidate identity attribute in the sets of candidate identity attributes. The program identifies, based on the sets of scores, an identity attribute from the sets of candidate identity attributes that identifies the entity having the entity attribute specified in the document.