Research

Preprints

Preprints are scholarly articles, shared by the author, that have not completed the peer review process. Authors may share preprints to establish priority in scientific discoveries, to demonstrate research progress for potential employers or grant funders, and to invite collegial feedback and discussion.

Here are some examples of preprint repositories:

• arXiv
• PsyArxiv
• BioRxiv
• MedRxive

Postprints

Postprints are scholarly articles, shared by the author, that have undergone revision following the peer review process but are not yet published.

For example, Elsevier is a founding member of the CHORUS service, which uses publisher infrastructure to facilitate access, discovery, and preservation of peer reviewed articles in the form of postprints. Elsevier provides open access to accepted manuscripts (postprints) authored by researchers affiliated with participating CHORUS agencies and universities. This expands access to research for libraries, which would otherwise have no access without a subscription to the journal. For more information about Elsevier and CHORUS, see the publisher's website: https://www.elsevier.com/open-access/chorus 

Should I cite a preprint or postprint in my research paper?

The APA style guide says that ideally, one should use and cite the final, published version of a work, but it does offer citation examples for preprints. The National Institutes of Health (NIH) require the digital object identifier (DOI) and object type (preprint, protocol) to be included in citations to help reviewers recognize non-peer reviewed or interim sources, and to identify the specific version being referenced.

Postprints have completed the peer review process and have been accepted for publication. In some instances, a postprint article may not yet be published. In other instances, a postprint article may be open access while a finalized version of the article may be published and accessible behind a paywall.

For best practice: 

1. Carefully evaluate of sources that are not peer reviewed.
2. Investigate the criteria of preprint archives.
3. Seek peer reviewed evidence that corroborates the findings of the preprint.
4. Clearly indicate if you use preprints in your research.

For more information see this NIH learning resource on preprints: https://www.nlm.nih.gov/oet/ed/pmc/preprints/03-300.html 

You may also wish to use the RADAR evaluation criteria to assess preprint sources.