Preprints

A preprint is a scientific manuscript that is uploaded by the authors to a public server. The preprint contains data and methods, but has not yet been accepted by a journal. While some servers perform brief quality-control inspections (for more details on the practices of individual servers, see asapbio.org/preprint-servers), the author’s manuscript is typically posted online within a day or so without peer review and can be viewed (and possibly translated, reposted, or used in other ways, depending on the license) without charge by anyone in the world. Most preprint servers support versioning, or the posting of updated versions of your paper based upon feedback and/or new data. However, most servers also retain prior preprint versions which cannot typically be removed to preserve the scholarly record. Preprints allow scientists to directly control the dissemination of their work to the world-wide scientific community.

Many preprint servers are integrated with one or more journals, making it possible to submit to both a server and a journal at once. View these integrations in the Preprint Server Directory.

Preprint servers can also serve as a “marketplace” for journal editors to invite submissions to their journals. PLOS Genetics has “preprint editors,” described in this article. Proceedings of the Royal Society B also have a preprint editorial team. Read more on our page about journal policies and practices.

Commentary on preprints (whether on the preprint site, on social media, or on sites such as preLights, PREreview, or Peer Community In) can help authors to improve their paper, and could also be used to inform the journal peer review process. For example, PLOS is piloting a program in which authors can opt-in to having community comments on preprint servers considered by editors along with traditionally-submitted peer review. The Review Commons platform (a collaboration between ASAPbio and EMBO) allows authors to post refereed preprints which can also be submitted to affiliate journals.

In the physics community, preprints posted on arXiv clearly establish priority of discovery since they have a time stamp, are publicly available and are widely cited (for more on arXiv, see Paul Ginsparg’s comments on scooping). An article on the topic of priority in the life sciences community by Ron Vale and Tony Hyman has appeared in eLife.

A review process is considered “double blind” if neither authors nor reviewers are aware of one another’s identities. Though it is relatively rare in the life sciences, it is more prevalent in social science and the humanities. Double blind review is one approach to mitigating biases in review, which can range from a bias against female corresponding authors (noted in studies of Frontiers, eLife, and AGU journals) to a bias towards authors within reviewer’s own co-author networks. For those journals and disciplines that use double blind review, it is an important part of their peer review process.

However, double blind peer review cannot eliminate all biases since many decisions fall with editors, and because many reviewers can already successfully guess the identity of authors. As summarized by Hilda Bastian: “The rate of failure of blinding [in 8 trials] was high: average failure rates ranged from 46% to 73% (although in 1 journal within one of the trials it was only 10%).” The rates of blinding failure may be influenced by how stringently authors obfuscate their identities in the manuscript, for example in referencing previous work.

Preprints might make it more difficult to preserve blinding. Currently, no preprint servers enable anonymous posting; doing so could compromise many of the benefits of preprints, such as visibility and recognition, and raise challenges related to ethical disclosures. COPE discourages pseudonymous preprint posting for similar reasons. That said, there are also many other sources of information that could compromise blinding. For example, seminar announcements, conference abstracts or programs, or social media posts are all searchable on the web. It is expected, however, that referees participating in double blind review will not attempt to discover the identities of manuscript authors, and will recuse themselves from reviewing papers with authors known to them.

This means that any early visibility of work can either harm the integrity of the double blind review process (if reviewers ignore requests to avoid attempting to identify authors) or make it more difficult to find suitable reviewers. While exacerbated by preprints, this problem is by no means unique to them.

The following have been raised as possible negative consequences of preprints.

• Poor quality and irreproducible data will be posted in preprint form.
• Scientists will rush out data pre-maturely to claim priority and get credit.
• Scientists will try to “scoop my work” if I post as a preprint.
• Reporters and other non-specialist will use the findings without recognizing the interim nature of papers.

Poor quality publications, irreproducibility, and scooping are already issues with our journal system, but there is no current evidence that the situation will worsen with preprints. Most of these (with the exception of human research) have been tested with physics research and have not come to pass with arXiv; nor is there any indication that these problems are surfacing in biology preprints. See the Q&A on scooping by Paul Ginsparg, founder of arXiv.

In practice, these tendencies are mitigated by the powerful driving force of scientists to develop and maintain a good reputation within the scientific community. Reputation is the single most important factor for developing a sustained career in the sciences. Even for scientists who voice the above concerns, when asked if they might be tempted to behave in such manners they immediately respond “no.” In fact, in some instances, poor quality/irreproducible work might be spotted by the community and corrected before reaching final publication in a journal.

Note that preprints are considered public disclosure for the purposes of patenting.

Europe PMC began indexing preprints in July of 2018. Preprints are also indexed in search tools such as Google Scholar, PrePubMed, and OSF preprints.

On June 1, 2020, NCBI announced a pilot to include NIH-funded preprints in PubMed Central, beginning, in the first phase, with preprints relevant to COVID-19.