The Evolution of MetaMap, a Concept Search Program for Biomedical Text

MetaMap1 is a widely available program providing access to the concepts in the UMLS ® Metathesaurus® from biomedical text. MetaMap arose in the context of an effort to improve biomedical text retrieval, spe-cifically retrieval of MEDLINE®/PubMed ® cita-tions.2,3 It provided a link between the text of biomedical literature and the knowledge, including synonymy relations, embedded in the Metathesaurus. Early MetaMap development was guided by linguistic principles which provided both a rigorous foundation and a flexible architecture. After some experience with MetaMap, it became clear that it could be applied to tasks other than retrieval, including text mining,4 classification, question answering,5 knowl