What Is a Preprint?
A preprint is a version of a research paper that authors share publicly before it has been peer reviewed and published in a journal. Preprints are posted on online servers and can be read for free by anyone. They allow research to be shared quickly, and they have become common in many fields, especially physics, mathematics, computer science, biology and, more recently, medicine and social sciences.
Why researchers post preprints
- Speed: peer review and publication can take months, and a preprint makes results available immediately.
- Feedback: other researchers can comment and suggest improvements.
- Establishing priority: a dated posting records when the work was shared.
- Access: preprints are free to read.
- Transparency: readers can see how a paper changes between versions.
How they work
Authors upload a manuscript to a preprint server, which may carry out basic checks, such as scope and plagiarism screening, but not full peer review. The paper is assigned an identifier and may receive updates through new versions. Later, the authors may submit it to a journal. If accepted, the published version appears, and many servers link to it.
Risks
Because preprints have not been reviewed by independent experts, they may contain mistakes, weak methods or overstated claims. In fast-moving areas such as health, preliminary results can be misinterpreted by media or the public, and some preprints are never published or are substantially revised. Readers need to judge them with care.
Using preprints as a student
- Check your instructor's rules, since some assignments require peer-reviewed sources.
- Label them clearly as preprints in your writing and citation.
- Look for the published version and use that where possible.
- Check the date and version, since the content may change.
- Weigh the evidence critically, looking at the methods and the authors' credentials.
- Avoid relying on a single preprint for important claims.
Citing
Most citation styles have formats for preprints, including the server name, identifier and version. Check your style guide.
Other uses of the word
Some publishers also use "preprint" to mean the manuscript as submitted, before review, and "postprint" or "accepted manuscript" for the version after review but before final formatting.
Related terms
See peer review, open access, scholarly journal, DOI and gray literature.
Frequently asked questions
Is a preprint reliable?
It may be, but it has not been peer reviewed, so errors may remain and conclusions may change. Treat it with care, and look for a published version.
Can I cite a preprint in my assignment?
Often yes, if your instructor allows it, and you should label it clearly as a preprint. Check whether it has since been published and cite the published version if so.
Where are preprints posted?
On preprint servers, which exist for many fields, such as physics, mathematics, biology, medicine and social sciences, and in some institutional repositories.