A Preprint Trial for PubMed Central

The National Library of Medicine (NLM) has begun including preprints* deriving from NIH-funded research in its PubMed Central (PMC) and PubMed databases, beginning on June 8th. The goal of the NIH in adding preprints is to enable faster discovery and dissemination of research, all while continuing to work to keep trust in the reliability and usability of NIH research resources. 

*As a reminder, a preprint is a:

  • scholarly manuscript
  • posted on an open access platform
  • before or in parallel with the peer review process

For Searchers and Readers
Preprints can be specifically searched:

Or, to exclude preprints, use the Boolean NOT operator, for example:

Starting with Covid-19 related preprints, the NLM will expand its pilot test after workflows are established to include preprints from other NIH-funded research. This pilot test will last a year, after which the NLM will review results and decide if they feel it is beneficial to continue to archive preprints. An NIH workshop on the topic called this a “controlled” approach to integrating preprints, as their use in the biomedical discipline is still evolving. It is also useful to note for context that Europe PMC has been adding preprints to its database since 2018.

The preprints that are added to PMC will be clearly labeled (similar to the image below), making it obvious to readers that this article has not yet undergone peer review. This banner announcement will also be present in preprints that are found while searching PubMed.

For Authors and NIH Grantees

This NLM project comes a few years after the NIH published a notice that strongly encourages the citation of preprints in award applications and progress reports. The NLM is not planning to add any new requirements for NIH awardees related to preprints, and PMC will not become a comprehensive preprint discovery resource, as it will only include NIH funded work.

In their effort to maintain the quality of their database, it is useful to note that the NLM will not be searching for and pulling NIH funded preprints from everywhere. Instead, they will be focusing on gathering preprints only from active awards, and they will search a small and carefully curated list of preprint servers that meet their reliability criteria.

The NLM will be permanently archiving the preprints it includes during this pilot session, and item records will include a visible link to other versions of the preprint article, and to the eventual published version of the article. However, NLM staff also encourage authors to make sure they notify journals they submit to if they have posted a preprint version of the article anywhere online. This is the surest way for authors to make sure that their preprint stays linked with the final peer reviewed copy of an article.

As the pilot project grows over the summer, and the focus switches to archiving non-Covid related preprints, the NLM will also be encouraging authors to include their preprints in their My Bibliography account, and to link their grant award to those preprints in ERA commons, to make sure that their preprint does not get missed.

Learn more about the NLM’s trial at:

Learn more about preprints from the Scott Library’s Online Guide: https://jefferson.libguides.com/OpenAccess/preprints

You can also provide direct feedback about this pilot by e-mailing pmc-preprints@ncbi.nlm.nih.gov