MEDLINE Policy on Indexing Electronic Journals
When a journal is indexed in MEDLINE®, NLM® has the responsibility to ensure that the public will have permanent access to the articles cited. For print journals, NLM does this by including a copy of each indexed journal in the NLM physical collection. PubMed Central® (PMC) is the NLM official electronic journal archive and a digital extension of its print collection. NLM recommends that an electronic journal that is selected for MEDLINE make itself part of the NLM permanent collection by depositing its articles in PMC.
The policy defined here 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. However, this policy will be expanded in the future to include publications where substantial content is available only in the online version of the publication. The first phase of the new indexing policy will focus on electronic-only journals.
Once an electronic journal has been selected for MEDLINE indexing (see MEDLINE Journal Selection fact sheet), it must meet three other conditions in order to be included in MEDLINE. It must:
- Provide NLM with XML-tagged data of its bibliographic citations.
- Provide robust current access to all of its content.
- Have an acceptable arrangement for permanent preservation of, and access to, the content.
Preferred arrangement for access and preservation
The preferred means for a journal to satisfy conditions 2 and 3 is to deposit all its content in PMC under a full participation agreement, which includes permission to redistribute the content to PMC International (PMCI) centers. Participation in PMC involves submission of full-text XML for all content at time of publication.
A journal may impose an embargo of up to twelve months on free access to its content in PMC. However, for the purpose of this policy, if the journal applies an embargo in PMC, it must also provide NLM with immediate access to the content at a publisher or third-party site under a license that allows efficient support of NLM operations, onsite services, and interlibrary loan (without delivery method or geographic restrictions).
Optional arrangement for access and preservation
If a journal chooses not to participate in PMC, it may satisfy conditions 2 and 3 above by doing ALL of the following:
- Provide NLM with immediate access to its content at a publisher or third-party site under a license that allows efficient support of NLM operations, onsite services, and interlibrary loan (without delivery method or geographic restrictions).
- Submit a PDF/A copy of each article to NLM along with the XML-tagged citation data. NLM will use these PDFs only for internal operations such as journal indexing.
- Promptly deposit tagged, full-text content in a certified1 third-party repository able to provide robust access to NLM and NIH if there is a trigger event (e.g., publisher ceases operations and title is not available from another source, catastrophic failure of publisher’s delivery system).
Example Scenarios that would Meet these Requirements
- Deposit in PMC with immediate free access to all content.
- Deposit in PMC at time of publication, with a one-year embargo on free access, plus immediate access to the content at a publisher site under qualifying license terms.
- Submission of PDF/A to NLM for each article at time of publication, and immediate access to the content at a publisher site under qualifying license terms, and deposit in a certified repository1 with arrangements for robust access if there is a trigger event.
- "Certified" according to the Trustworthy Repositories Audit and Certification Checklist (TRAC) and other metrics developed by the Center for Research Libraries (CRL) (see the CRL Certification and Assessment of Digital Repositories page for the current list of certified repositories).
- This policy on MEDLINE indexing does not change the NIH Public Access Policy, which mandates the deposit of all NIH-funded, peer-reviewed journal in PMC. NIH-funded authors still need to ensure that their articles are properly deposited in PMC, as directed by the Public Access Policy.
- For additional information, please see the FAQ: MEDLINE Indexing Requirements for Electronic Journals.