Contains structured abstract labels identified from the 2010 MEDLINE Baseline and the MEDLINE daily files from November 24, 2009 to June 2, 2010 that have PMID counts of 25 or more PMIDs per label as well as some with fewer than 25 PMIDs because they were straightforward maps. These 1,456 entries account for 98.50% (6,674,229 of the 6,775,741 of total instances) of possible structured abstract labels identified in the data. There remains an extremely long tail of structured abstract labels with instances of 24 or fewer PMIDs. Evaluation and mapping of labels work continues at NLM; more values will be available for the 2012 MEDLINE Baseline.
Column 2: NLM CATEGORY
Contains the NLM Category which is one of five broad conceptual groups, or Metacategories, to which each structured abstract label was mapped. The five are: BACKGROUND, OBJECTIVE, METHODS, RESULTS, CONCLUSIONS.
For researchers or implementers who want to use these NLM Categories, NLM offers the following ranking guideline based on our indexing experience on the value of the section of the abstract in identifying pertinent main subject concepts discussed in the article:
is electronically submitted by publishers as part of supplied citations' abstracts; or
is identified by NLM PubMed data import procedures.
To accommodate this broadened definition, NLM made a mid-year 2013 change to the NLMMedlineCitationSet DTD (used for MEDLINE/PubMed processing) which added a new NlmCategory attribute valid value, UNASSIGNED. The UNASSIGNED NlmCategory is used for labels in structured abstracts that NLM has not yet mapped to one of five categories, i.e., BACKGROUND, OBJECTIVE, METHODS, RESULTS, CONCLUSIONS.
While the UNASSIGNED attribute values will appear in the PubMed data, versions of Updated Label List and NLM Category Mappings will continue to list only labels that have been mapped to the five other categories. NLM may in the future provide a list of labels with UNASSIGNED values for display purposes only.