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2011 MARCH–APRIL No. 379
March 10, 2011 [posted]

Updated Policy for MEDLINE Indexing Requirements for Electronic Journals

The revised NLM® MEDLINE® Policy on Indexing Electronic Journals is available at This policy concerns electronic journals that are indexed in the MEDLINE/PubMed® database.

The revised policy applies only to the MEDLINE indexing of electronic journals. As journal publishing evolves, the journal of record for many publications is the online version of the journal, with much material only appearing online and not in a print equivalent of the journal. The NLM policy for indexing articles from electronic journals is also evolving and the following requirements will initially apply to electronic-only journals. This policy will be expanded in the future to include publications that are not exclusively electronic-only journals but where substantial content is found only in the online version of the publication.

The updated policy will initially be applied to electronic-only journals which have applied for and been recently approved for inclusion in MEDLINE, and journals currently indexed in MEDLINE that have switched or will switch to being electronic-only.

There are three required conditions that electronic-only journals must meet in order for the journal to be indexed in MEDLINE:

  1. Provide NLM with XML-tagged data of its bibliographic citations.
  2. Provide robust current access to all its content under a license allowing efficient support of NLM operations, onsite services, and interlibrary loan.
  3. Have an acceptable arrangement for permanent preservation of, and access to, the published content.

For conditions 2 and 3, NLM must be satisfied that all articles published in an electronic-only journal are available in a digital archive. We seek to ensure that our users will always have access to the full text of every article cited in MEDLINE. The permanent archive must be either by:

Participation in PubMed Central is the preferred method for an electronic-only journal to meet this NLM policy; the new version identifies that acceptable alternatives are third-party archives that meet certification standards, as outlined by the Trustworthy Repositories Audit and Certification Checklist (TRAC) and other metrics developed by the Center for Research Libraries.

The original policy stated that electronic-only journals must submit all articles published to a digital archive; that permanent archive was either PubMed Central or another site that is acceptable to NLM. The new policy identifies the standards appropriate for an archive, as well as the requirement for depositing PDF/A copies of published articles, if a journal does not deposit to PMC.

NLM will begin the implementation of this policy beginning May 1, 2011. There are cases where journals currently indexed in MEDLINE have switched or may switch over to being electronic-only publications. NLM will notify these journals about the new electronic-only journal indexing policy, and will provide a generous timeframe to allow these journals to comply with the policy so their inclusion in MEDLINE will continue.

Additional information on the policy is available from the FAQ: MEDLINE Indexing Requirements for Electronic-Only Journals.

By David Gillikin
Bibliographic Services Division

Gillikin D. Updated Policy for MEDLINE Indexing Requirements for Electronic Journals. NLM Tech Bull. 2011 Mar-Apr;(379):e4.

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