MEDLINE policies and processes are guided by those of the National Library of Medicine (NLM) and National Institutes of Health (NIH), as well as current best practices for scientific publishing and scholarly communication. The Literature Selection Technical Review Committee (LSTRC) was established to review journal titles for MEDLINE and assess the quality of their contents. In addition, the LSTRC advises the NLM on matters of policy relating to the review of biomedical journals for MEDLINE.
For a journal to be indexed for MEDLINE, NLM expects that the journal and publisher will meet NLM’s standards for MEDLINE and the NLM Collection over time. These standards include maintaining the scientific quality of the publication, supplying quality data to PubMed in a timely manner, following industry best practices, demonstrating sustainability, notifying NLM of journal or publisher changes, and adhering to journal access and preservation requirements. More details on each of these expectations are provided in the following sections.
NLM considers the suitability of a journal for the NLM Collection and its scientific and editorial quality in determining if it merits inclusion or continued indexing in MEDLINE. See Journal Selection for MEDLINE for details.
See Reevaluation for information on when NLM may reevaluate a MEDLINE journal and the reevaluation process.
MEDLINE journals must provide citation and abstract data to PubMed in an XML format that conforms to the PubMed DTD and meets the minimum data criteria. Please refer to XML Help for PubMed Data Providers for detailed technical requirements for PubMed data submissions.
PubMed does not accept citation and abstract data in PDF, Word, or other DTDs.
Currently indexed MEDLINE journals must supply citations to PubMed within six months of final publication and submissions must continue to meet PubMed’s technical quality standards consistently in order to remain indexed for MEDLINE. If a journal does not continue to meet these requirements, NLM may cease indexing the journal for MEDLINE.
NLM looks for ongoing publisher conformance with guidelines and best practices published by professional organizations, including Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals from ICMJE and Principles of Transparency and Best Practice in Scholarly Publishing (joint statement by COPE, DOAJ, WAME, and OASPA).
NLM also recommends that electronic journals follow the recommendations of PIE-J: The Presentation & Identification of E-Journals (NISO RP-16-2013), particularly in the areas of title presentation, accurate use of ISSN, and citation practices.
If a publisher is found to not be following established industry best practices, NLM will cease collecting the publisher’s journals and not accept applications to any of the NLM Literature databases, including MEDLINE and PubMed Central (PMC), for a minimum of three years.
NLM expects a currently indexed MEDLINE journal to have a posted publishing schedule, maintain its stated publishing schedule, and actively publish primary content.
If a currently indexed MEDLINE journal repeatedly fails to publish primary content, does not adhere to its stated publishing schedule, or does not publish any primary content over a two-year period, NLM will cease indexing the journal for MEDLINE. The journal may reapply if/when it resumes publishing, subject to the minimum requirements for reapplications.
Currently indexed MEDLINE journals must notify NLM of any significant changes to the journal’s title, ownership or publisher, publishing format, subject matter scope, editorial board, or practices. NLM will determine whether the changes are considerable enough to warrant a new application and evaluation by LSTRC or a publisher review by NLM. Changes to a journal that may impact a journal's MEDLINE status include:
- The merger of two journals when one of the journals is not indexed for MEDLINE.
- A major title change that requires a new ISSN.
- A significant change in focus (aims and scope) and/or editorial board.
- A change in publisher. NLM may request additional information and complete a review of the publisher policies and practices. Alternatively, if the new publisher is not an organization from which NLM is currently acquiring materials for the Collection, NLM may cease indexing the journal for MEDLINE (see Publisher Practices).
- A print-only journal begins publishing an electronic version of the journal (see Access and Preservation Requirements for more information).
If a currently indexed MEDLINE journal undergoes a title change, NLM may reevaluate the journal if it is determined that there are significant changes in editorial policies, editorial board, or subject matter scope. In such a case, the journal will be asked to submit an application once 20 articles have been published or after one year (as long as there is sufficient primary content available for review).
When a journal is indexed for MEDLINE, NLM ensures that the public will have permanent access to the articles cited. As such, journals that are selected for MEDLINE must remain compliant with the access and preservation requirements described in the following sections in order to remain indexed for MEDLINE.
For print-only journals indexed for MEDLINE, NLM ensures permanent access to and preservation of the articles by including a copy of each indexed journal volume and/or issue in the NLM physical collection. NLM must receive subscriptions in a timely manner for print journals to be considered in compliance with the access and preservation requirements.
NLM considers a journal to be an electronic journal when the complete content is published online. Electronic journals with print-on-demand options or that provide an annual print version of their content are considered by NLM to be electronic journals with regard to MEDLINE indexing and compliance with MEDLINE policies.
NLM requires electronic journals to meet the following requirements to ensure permanent access:
- Provide NLM with robust current access to the journal’s content.
- Have an acceptable arrangement for permanent preservation of, and access to, the content.
For newly recommended electronic journals, full acceptance to MEDLINE will be dependent on the journal successfully complying with both requirements by the given deadline.
Electronic journals must remain compliant with both requirements in order to be eligible for continued MEDLINE indexing. If a currently indexed electronic journal is found to no longer meet either of the requirements, or if a currently indexed journal begins publishing an electronic version or becomes an electronic-only publication, NLM will work with the journal or publisher to ensure compliance with both conditions by the applicable deadline.
The access and preservation requirements were first established by NLM in May 2011 and applied exclusively to electronic-only journals. As of March 2021, these requirements have been updated to apply to any journal with an electronic version (i.e., both electronic-only and electronic-and-print journals). During the initial implementation phase, the updated policy will be applied only to newly accepted journals and currently indexed print-only journals that begin publishing an electronic version. At present, the original policy (i.e. applicability solely to electronic-only journals) remains in effect for electronic journals that were accepted to MEDLINE prior to March 2021.
The individual requirements for electronic journals are described in detail in the following sections.
To be considered for MEDLINE, an electronic journal must provide at least one of the following means of institutional access as defined in the NLM Collection Development Guidelines:
- immediate access to the full text with no requirement for user registration; or
- institutional access via IP authentication, under a license that allows efficient support of NLM operations, onsite services, and interlibrary loan (ILL) requirements.
NLM defines efficient ILL as the ability to fulfill ILL requests through the delivery mechanism specified by the requesting library and without regard to geographic location of the requesting library. Publishers are required to allow ILL via post, fax, and two out of the following three electronic delivery methods: proprietary vendor electronic delivery system, web delivery, or email.
For licensed content, NLM requires post-cancellation access, meaning continued access to all years for any subscribed content, in the event the Library cancels a title.If more than one title is licensed from the same publisher and at least one title is subject to the Access and Preservation Requirements, then all titles subscribed to from that publisher by NLM and covered by the license agreement must be provided with the same interlibrary loan terms. Any new titles added to the license must also be under the same terms. If an existing license does not contain satisfactory language related to interlibrary loan terms, then the license must be amended before indexing can commence or continue.
Electronic journals must ensure that their content is preserved in either a certified third-party repository or in PubMed Central (PMC).
A certified repository is one that has been “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). A certified repository provides 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).
PMC is a free full-text archive of biomedical and life sciences journal literature at NLM. In keeping with NLM’s legislative mandate to collect and preserve the biomedical literature, PMC serves as a digital counterpart to NLM’s extensive print journal collection. For information about the PMC application requirements and process, please see How to Include a Journal in PMC.
NLM expects journal content to be deposited in the chosen repository in a timely manner to ensure that preservation compliance is maintained.
Electronic journals that are conditionally accepted to MEDLINE, as well as currently indexed journals that have a relevant change of publication format must apply to an acceptable repository within three months of being notified of the preservation requirement by NLM, and must fully comply with both the access and preservation requirements within twelve months.
If at any point a currently indexed electronic journal stops meeting the access and/or preservation requirement(s), the journal will have six months to become compliant again.
If a conditionally accepted journal does not comply with the access and preservation requirements by the given deadline, its application will be closed. If a currently indexed journal fails to comply with the requirements by the given deadline, NLM will cease indexing the journal and its indexing status will be changed to “Not currently indexed for MEDLINE”. In either case, the journal will be required to reapply in order to be reconsidered for MEDLINE.
The application and selection processes for MEDLINE are described in detail at How to Include a Journal in MEDLINE and Journal Selection for MEDLINE. NLM selection decisions for MEDLINE are generally final. Applicants are expected to be responsive to NLM queries and requests throughout the entire application process.
Upon selection, NLM continues to monitor journals for conformance with NLM’s expectations for MEDLINE Journals to maintain the quality of the database.
If a publisher has not previously submitted a journal application to NLM (for MEDLINE or PMC), NLM will generally complete a review of the publisher policies and practices upon receipt of an application (see Publisher Practices). This review determines whether a publisher’s journals are eligible to be considered for the NLM Collection. A publisher review is completed prior to initiating the journal application process. As such, the application period will be longer for these titles. NLM may also request additional publisher information as part of this review.
Reapplication timelines will vary based on several factors:
- Journals that do not pass the initial application screening are eligible to reapply two years (24 months) after the date the review is completed.
- Journals that are not recommended for MEDLINE after their first LSTRC review are eligible to reapply two years (24 months) after the date the review is completed.
- Journals that are not recommended for MEDLINE after their second or subsequent LSTRC reviews are eligible to reapply three years (36 months) after the date the review is completed.
- Journals that cease indexing as a result of not meeting MEDLINE’s Publishing Schedule policy are eligible to reapply when they resume publishing in line with the policy and publish a minimum of 20 peer-reviewed articles.
- Journals that cease indexing or applications that are closed as a result of not meeting MEDLINE’s Access and Preservation Requirements are eligible to reapply as soon as they demonstrate their ability to comply with the policy.
Any reapplication to MEDLINE will be processed as a new application and will be subject to initial application screening, scientific quality review, and technical evaluation (if applicable).
If a journal reapplies after previously not meeting MEDLINE’s Scientific Quality Standard, a minimum of 20 peer-reviewed articles (e.g., original research or review articles, clinical case reports) must have been published between the initial notification from MEDLINE and the date the journal is eligible to submit a new application. If a journal has not published a minimum of 20 peer-reviewed articles by the date it is eligible to reapply, the journal should wait until the minimum has been met before submitting the new application. Please note that any content published prior to the date of the previous rejection is ineligible for indexing for MEDLINE and is, therefore, out of scope for the review.
An application will be considered inactive and closed if the journal or publisher ceases to respond to communications from the MEDLINE applications team.
An application for a journal that is recommended for MEDLINE and conditionally accepted will be considered expired and closed if:
- the journal does not successfully complete the PubMed Technical Evaluation within six months of their recommendation for MEDLINE, or
- the journal does not fully comply with the Access and Preservation Requirements within the deadline provided by NLM.
To maintain the quality of the archive, NLM regularly reviews current MEDLINE journals for conformance with NLM’s Expectations for MEDLINE Journals.
NLM will reevaluate a journal for continued participation in MEDLINE if
- there are problems identified with article(s) that a publisher fails to address or that appear to be systemic;
- there are verifiable concerns about the scientific or editorial quality of the journal content; or
- there are significant changes in a journal’s ownership, policies, subject matter scope, editorial board, or practices.
The reevaluation process for a current MEDLINE journal is similar to the review process for new journal applications to MEDLINE, including evaluation by the LSTRC. See Journal Selection for MEDLINE for details on how journals are assessed.
Before the reevaluation begins, MEDLINE staff will notify the journal of NLM’s concerns. If the reevaluation coincides with the journal switching to a new data provider who has never delivered content to PubMed, the standard PubMed technical evaluation (and therefore submissions to PubMed) will be put on hold until the reevaluation is complete. The reevaluation process will focus on recent content.
To begin the process, the publisher must submit an application to the MEDLINE Publisher Portal. If an application is not received within 90 days of being notified by NLM, the journal’s indexing status will be changed to “Not currently indexed for MEDLINE” and NLM will cease indexing the journal for MEDLINE.
If the journal is found to meet MEDLINE’s scientific and editorial standards, MEDLINE will continue to accept and index content from the journal. If the journal is found to no longer meet NLM’s standards, NLM will cease indexing the journal for MEDLINE and the journal’s indexing status will be changed to “Not currently indexed for MEDLINE.” The journal will be eligible to reapply two years after the date the LSTRC review was completed. For journals whose PubMed technical evaluation was put on hold, no additional content, including any articles submitted or published during the holding period, will be accepted for indexing. The journal will be eligible to reapply two years after the date the LSTRC review was completed.
NLM’s decision to cease indexing a journal for MEDLINE is generally final. NLM encourages journals to use feedback resulting from the reevaluation review to improve the publication’s overall scientific and editorial quality.
NLM decisions for MEDLINE and PMC applications are generally final and not subject to appeal except in the limited circumstances described in this policy. NLM will only consider an appeal if an appeal letter:
- is received within 60 calendar days after issuance of the review report,
- describes a flaw or perceived flaw in the review process for that particular application, and is based on factual error(s) apparent in the review report that could have altered the outcome of review substantially.
Appeal letters based solely on differences of scientific opinion will not be accepted. A letter that does not meet these criteria will not be considered an appeal letter and will be rejected.
Upon receipt, NLM staff will consider the basis for and evaluate the merit of the appeal. The two possible outcomes of this review are:
- NLM may accept the appeal and recommend that the application be re-reviewed. If the appeal is accepted, the original application will be reevaluated without additional materials or modifications. If the second evaluation results in a rejection, the journal reapplication date will be determined based upon the new decision date rather than the original decision date. The outcome is final and cannot be appealed again.
- NLM may concur with the original decision and deny the appeal. (Please note, that although factual errors or other issues may be evident, NLM may determine that these factors were unlikely to alter the final outcome of the original decision and deny the appeal.) If the appeal is denied, the reapplication date for the journal will remain based on the time of the initial decision.
NLM will notify the applicant of the decision to accept or deny an appeal within 30 calendar days. The recommendation of NLM concerning resolution of an appeal, whether to accept or deny, is final and will not be considered again by the NLM through this or another process.
A journal is eligible to submit an application to MEDLINE as long as it meets the following criteria regarding scope and language, as well as the pre-application requirements outlined on the How to Include a Journal in MEDLINE page.
Before evaluating the scientific and editorial quality of a journal, NLM will consider the subject matter, presence of publicly stated policies, article content types, and other scope-related matters. A journal should be in scope for the NLM Collection, as well as MEDLINE, specifically, to be considered for indexing.
Journals that do not clearly meet the subject scope and content requirements for the NLM Collection and MEDLINE may require more in-depth review. In such cases, the application period may need to be extended or the applicant may be encouraged to reapply at a later date if the journal scope evolves.
To be eligible for MEDLINE a journal must publish generally within the biomedical and life sciences. The NLM Collection Development Guidelines define NLM’s collecting interest in a subject, and the level of intensity at which it is applied. NLM focuses on the subject matter of the peer-reviewed content that a title has published in the last two years, especially as it pertains to human health and medicine as per the NLM legislative mandate, to determine whether a journal is in scope for the Collection. NLM is unable to provide a comprehensive list of articles reviewed in making a scope determination.
For indexing for MEDLINE, NLM currently selects publications that it considers to be journals, as defined by the Collection Development Journals Guideline.
In addition, NLM considers the following factors in determining if a journal is in scope for MEDLINE:
- The journal must be peer reviewed and have a clearly stated peer review policy.
- The journal must be responsible for the peer review process and editorial processes underlying the published articles.
- The primary content of the journal should consist of one or more of the following article types:
- Original research
- Review articles
- Clinical case reports
- Data descriptor articles (Note: Datasets should be in publicly accessible repositories and fully referenced in the articles.)
- Descriptions of clinical or surgical procedures
- Analyses of philosophical, ethical, or social aspects of the health professions or biomedical sciences
Publications that consist primarily of reprinted articles, reports of association activities, abstracts of the literature, news items, or book reviews will not usually be considered for indexing.
Journals that applied to PMC within the last two years and were not found to meet the NLM Collection scope requirements, suitability for the NLM Collection, or PMC’s scientific quality standard are not eligible to apply to MEDLINE.
Criteria for the review of non-English titles are the same as for those written in English. In order to extend the accessibility of the journal’s content to a wider potential readership and enhance indexing with MeSH terms, all primary articles (i.e. peer-reviewed articles) must have English abstracts and titles. For journals applying to MEDLINE, all peer-reviewed content published in the past 12 months must contain English abstracts and titles before the journal is eligible to apply.
This section outlines MEDLINE expectations for the handling and deposit of different types of content.
For journals that are selected for MEDLINE, indexing will typically begin with the current year/volume in which the journal meets the following conditions (where applicable):
- NLM must have access to the journal content, which is generally acquired through a subscription or license.
- Journals must be fully compliant with the Access and Preservation Requirements.
- The journal must have a method for submitting quality citation and abstract data in XML format to PubMed.
If the journal is within the first three volumes at the time of acceptance to MEDLINE, indexing may begin with the first volume/issue of the journal, unless
- the journal was determined by NLM to be out of scope for MEDLINE during that period;
- the journal was determined by NLM to not meet PMC quality standards during that period; or
- the journal was determined by NLM to not meet MEDLINE quality standards during that period.
NLM expects publishers to follow established industry best practices (e.g. ICMJE's Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals, and COPE’s Guidelines for retracting articles) for the handling of corrections, retractions, and expressions of concern.
See Errata, Retractions, and Other Linked Citations in PubMed for additional details.
MEDLINE expects publishers to follow the International Committee of Medical Journal Editors (ICMJE) recommendations on “Supplements, Theme Issues, and Special Series” and the related guidance in this section.
These best practices apply to:
- all supplements or special issues that are separately published by a journal;
- special sections or groups of articles within a regularly numbered issue of a journal if outside sponsorship, guest editorship, or a proprietary product as a topic are indicated; and
- supplements containing the proceedings of a conference, congress or other type of meeting sponsored or financed by an outside group.
Sponsorship or absence of sponsorship for journal supplements must be clearly indicated in both print and electronic versions of journals at the time of the original publication of the supplement issue.
If a journal supplement is sponsored by an outside organization, reports on a conference or other activity that was sponsored by an outside organization, or is devoted to a special topic that is in any way related to a proprietary product, then the articles in the supplement must contain the disclosure information described below. An “outside organization” is one not affiliated with the journal; it does not include the organization for which the journal is the publishing organ (e.g., the American Academy of Dermatology and the Journal of the American Academy of Dermatology), nor does it include any U.S. or non-U.S. government agency.
Disclosure information for authors must:
- specifically document any financial relationship that each author has with the sponsoring organization and the for-profit interests the organization represents, and with any for-profit product discussed or implied in the text of the article; and
- appear within the paginated text of the article and not elsewhere in the issue.
Disclosure information for editors or guest editors must:
- specifically document any financial relationship that each editor has with the sponsoring organization and the for-profit interests the organization represents, and with any for-profit product discussed or implied in the supplement; and
- appear in the supplement, preferably on the Table of Contents page.
Disclosure information must:
- include an explicit statement of no outside organization involvement; and
- appear in the journal issue, preferably on the Table of Contents page.