Preprints: What you need to know

In Knowledge Translation by Fadi BahodiLeave a Comment

Introduction: the history of preprints

Aashka is finally nearing the completion of her groundbreaking paper on an emerging influenza outbreak. She’s planning to submit it to a scientific journal when one of her team members asks her, “Why don’t we send it off to a preprint server first?” She doesn’t know much about this process and is afraid that depositing a preprint might interfere with publishing in a journal, which is her main goal.  

This post will go over what preprint servers are, their advantages and disadvantages, and the processes of submitting a manuscript to a preprint server. 

Preprints  are manuscripts that are posted to a preprint server before they have been published in a peer-reviewed journal.​1​ Preprint servers are research-sharing platforms that host preprints, and often include moderators, a brief screening process, and the ability for other researchers to comment on manuscripts.​2​ Preprints can be cited and receive a digital object identifier (DOI), and can be hosted permanently on the server. The first official preprint server launched in 1991, called arXiv, as a way for researchers to share information more openly and expeditiously, with a focus on the physical sciences.​3​ Over 2 million preprints are hosted now on arXiv alone.​3​ Several preprint servers hosting health sciences content now exist, including medRxiv, bioRxiv, SciELO Preprints, and Preprints with The Lancet.​2​

Preprints are now becoming more commonplace, especially since the start of the COVID-19 pandemic, with UNESCO even recommending that member states consider “promoting open science… in all stages of the scientific process… for example, preprints, clearly distinguished from final peer-reviewed publications.”​4​

The preprint screening process

The process of submitting an abstract or paper to a preprint server is rather simple and closely mirrors that of journals. This link is an example of an abstract submission process. Refer to the diagram below for a graphical summary.

Figure 1: The Pre-Print Screening Process


There are several advantages to preprints, especially in the medical community. Preprints allow fast and free information exchange between diverse fields of researchers, which can help encourage collaboration and discovery.​5​ For example, if an individual is conducting time-sensitive research, the preprint process allows for more rapid dissemination compared with traditional peer-review, which usually takes months or more. It also can allow researchers to get impactful feedback on their manuscript before it is published, as many preprint servers have commenting features.​6​ In addition, some journals now encourage or even require a manuscript to be hosted on a preprint server before it will be accepted for publication.​7​ It is also a way for researchers to protect intellectual property before publication in a peer-reviewed journal, as preprint servers provide a DOI and indexing. It can help researchers with academic promotion as research positions can often be evaluated by metrics such as the number of citations a researcher has accrued. Depositing a manuscript on preprint servers allows citations to begin accruing earlier. Some agencies, such as NIH, allow the listing of preprints on their biosketches (similar to CVs), enabling researchers to showcase their work in progress.​8​ 

The challenges, myths, and unwritten rules of preprints

While the reception of preprints is generally positive and recommended by many in academia and organizations like UNESCO, they come with few potential disadvantages. A few are mentioned below. 


A common fear for preprints is “scooping”, the concept that one’s ideas may be stolen in the period between preprint submission and journal publication. Preprints like arXiv have a timestamp on submissions, making it difficult to dispute the first publication. However, if a manuscript is quite far from completion, posting a preprint could theoretically allow time for another lab to repeat the experimental design. However, in reality, posting  on a preprint server could be beneficial, as it could establish priority, allowing a researcher to temporarily circumvent the variability of a multi-month submission process. 

Verdict: Myth 

Potential for errors and misinformation

Submitting to a journal is a multi-month process, which aids in ensuring that the research is accurate and robust, and generally makes the paper more presentable and easier to understand. While preprint servers do have an approval process, it is not as rigorous as peer-reviewed journals, arguably making papers more likely to have mistakes. In an evidence-based field like medicine, the accuracy of the research is critical. A recent paper that was submitted and accepted to a preprint server suggested that two mRNA vaccines might have a negative protective effect against the Omicron variant of COVID-19. It was widely circulated, despite inaccuracies in their methods and timing. After further peer review, the study was rescinded as the researcher’s data did not line up with their initial hypothesis.​9​ While preprints do state that the work is incomplete, preprint servers’ use of DOIs and structure similar to that of a journal publication could lend to them being used as evidence and propagate incorrect science amongst laypersons. 

Verdict: Disadvantage (Potential)

Impact on journal publication

There is a perception held by some researchers that posting a preprint will prevent or hinder journal publication as the main research findings will already be available publicly. Prior to COVID-19, many medical journals had policies against posting on a preprint server; however, the pandemic necessitated rapid access to information, and now many journals have adopted policies that often allow preprints to be considered for publication. Some journals require changes going from preprint to manuscript, however. In a related point, many researchers fear that posting a preprint and publishing an article counts as an ethical violation of “double publishing.” In actual fact, a preprint server is not a publisher, and manuscripts deposited on preprint servers should not be referred to as publications. 

Verdict: Depends!

Official positions of papers 

Several leading journals have statements on their websites regarding preprints. The Canadian Medical Association Journal (CMAJ) and the New England Journal of Medicine both will consider preprints and request that authors inform them of the preprint version.​10,11​ CMAJ encourages authors to edit their manuscripts in response to comments they have received.​10​ The Lancet and the British Medical Journal also accept preprints. ​12,13​ The Journal of the American Medical Association however notes that submissions with preprint versions “will necessitate making a determination of whether publication of the submitted manuscript will add meaningful new information to the medical literature or will be redundant with information already disseminated with the posting of the preprint.”​14​

Emergency medicine journals such as The Journal of Emergency Medicine, Annals of Emergency Medicine, and Resuscitation all will consider preprints for publication.​14–17​ The Canadian Journal of Emergency Medicine and Academic Emergency Medicine do not explicitly state whether or not they would accept preprints.​18,19​

Medical education journals such as Medical Education and Medical Teacher will consider preprints for publication.​20,21​ Academic Medicine states that they will consider preprints on a “case-by-case” basis.​22​Advances in Health Sciences Education state that they will consider preprint articles if the journal article submission is at least 90% similar to the preprint.​23​

JournalOfficial Position
Academic Emergency MedicineDo not explicitly state their position on preprints
Academic MedicineWill consider preprints for publication on a case-by-case basis
Advances in Health Sciences EducationWill consider preprints for publication – must be 90% similar to preprint
Annals of Emergency MedicineWill consider preprints for publication
British Medical JournalWill consider preprints for publication
Canadian Journal of Emergency MedicineDo not explicitly state their position on preprints
Canadian Medical Association JournalWill consider preprints for publication
Journal of the American Medical AssociationSubmissions with preprint versions “will necessitate making a determination of whether publication of the submitted manuscript will add meaningful new information to the medical literature or will be redundant with information already disseminated with the posting of the preprint”
Journal of Emergency MedicineWill consider preprints for publication
The LancetWill consider preprints for publication
Medical EducationWill consider preprints for publication
Medical TeacherWill consider preprints for publication
New England Journal of MedicineWill consider preprints for publication
ResuscitationWill consider preprints for publication
Table 1: Summary of Official Positions of Various Journals on Preprint Servers

The bottom line

Prior to 2019, the medical world was generally skeptical  of manuscripts posted as preprints, and preprint servers themselves. The COVID-19 pandemic necessitated rapid sharing of information that made preprints  a highly useful and accessible way of disseminating science. Preprints are an excellent way of facilitating knowledge exchange and carry relatively few risks regarding publication. Next time you are ready to publish your time-sensitive influenza outbreak paper, perhaps consider depositing the article on a preprint server first.

Figure 2: Medical Preprints Summary

This post was peer-reviewed by Lauren A. Maggio, PhD. Dr. Maggio is Professor of Medicine and Health Professions Education at the Uniformed Services University of the Health Sciences.  


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Fadi Bahodi

Fadi Bahodi

Fadi is a second-year medical student at McMaster University. His interests are in health innovation quality improvement and digital health.
Remi Kandal

Remi Kandal

Remi Kandal is a third-year medical student at the University of British Columbia Southern Medical Program. Her interests include health equity, knowledge translation, and medical education. In her spare time, she can be found lifting weights, jumping into any body of water, or falling off her mountain bike.
Remi Kandal

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Daniel Ting

Daniel Ting

Daniel Ting is an Emergency Physician and Clinical Assistant Professor at the University of British Columbia, based in Vancouver. He is the Editor-in-Chief of CanadiEM and a Decision Editor at the Canadian Journal of Emergency Medicine. He completed the CanadiEM Digital Scholarship Fellowship in 2017-18. No conflicts of interest (COI).
Daniel Ting
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