12. The apparatus of claim 9 , wherein the method further comprises training the statistical model to optimize a likelihood of labeling the at least a portion of the text string as corresponding to the particular entity type, based at least in part on the first and second concepts as features of the token.
9. Apparatus comprising: at least one processor; and at least one processor-readable storage medium storing processor-executable instructions that, when executed by the at least one processor, perform a method comprising: matching a token from at least a portion of a text string with a matching concept in an ontology, wherein the at least a portion of the text string has been labeled as corresponding to a particular entity type; identifying a first concept as being hierarchically related to the matching concept within the ontology; identifying a second concept as being hierarchically related to the first concept within the ontology; and training a statistical model to associate the first concept with a first probability of corresponding to the particular entity type and the second concept with a second probability of corresponding to the particular entity type, based at least in part on the labeling of the at least a portion of the text string as corresponding to the particular entity type.