Skip Navigation Bar
NLM logo

Unified Medical Language System® (UMLS®)

2009AA Outcome and Assessment Information Set Source Information


 (skip to: notes)

Semantic Type Count Percentage


  • Semantic Types are a set of 135 broad subject areas that provide a consistent categorization of concepts represented in the Metathesaurus. Semantic Types are arranged into two mutually exclusive hierarchies, Entity and Event.
  • Semantic Types help summarize the content of a source.
  • Each Metathesaurus concept is assigned at least one semantic type, many have more than one.
  • The report displays the most frequently assigned semantic types in descending order, up to a total of 1%.
  • The 'Count' field below is the number of concepts assigned a specific semantic type and containing at least one atom from the source.
  • The 'Percentage' field below is the count relative to the total number of concepts that contain an atom from that source.
  • The MRSTY file contains one row for each Semantic Type assigned to each concept. All Metathesaurus concepts have at least one entry in this file.
  • See UMLS Documentation, Section 3, Semantic Network

Last Reviewed: June 21, 2011