Why You Need to Know About Preprints

If you’ve been following COVID science – and who hasn’t? – you need to understand what a preprint is.

Source: Christo Anestev/Pixabay

Early in the pandemic, a tantalizing (but ultimately misleading) finding suggested that COVID was no more fatal than the flu. The release of this study, in April 2020, generated an enormous amount of media attention and fueled political polarization. The catch? The study was a preprint, not a peer-reviewed journal article. We promise this boring-sounding distinction is important, and can even make you sound smart at parties.

A Distinction with Meaning

Most of the time, when you read about a scientific finding in the news, that research has been published in a peer-reviewed journal. The peer-review process includes several reviewers—other scientists doing similar research who offer specific feedback on the manuscript—as well as a suggested verdict: accept, reject, or revise. It is rare for a first-draft article to be accepted as is, so most articles undergo one or more rounds of revision until the reviewers (and the editor overseeing all of this) feel that their concerns have been addressed. Many first drafts are ultimately rejected, or never get submitted to peer-reviewed journals in the first place.

So, what’s a preprint, then? A preprint is a draft of an article that is posted online for public access but has not yet undergone peer review. Preprints offer several benefits, including that new science is shared quickly, sometimes 14 months sooner than a peer-reviewed journal article. Generally, a preprint is later submitted to a journal and undergoes peer review, and, almost always, one or more revisions. It also may never get accepted. So, it’s a good bet that a preprint has more flaws than a published article. Indeed, the authors of the COVID-fatality study we mentioned above were roundly criticized for their methodology after their preprint went live, and they issued revisions shortly thereafter. Eventually, the paper was peer-reviewed and published with attenuated conclusions. But the damage was done. Even after revisions were issued, these data were cited to rail against COVID precautions and became one of the early rallying calls that politicized the pandemic.

A Preprint Primer

During the pandemic, we have all clamored for science to guide individual behaviors and societal policies, and to offer hope that we might eventually get a reprieve from the relentless waves of the disease. Scientists of all stripes have answered this call—psychologists, biologists, epidemiologists, and more. With scientific consensus changing rapidly, preprints have been an essential and valued part of the communication process. One study documented that about a quarter of COVID-related research articles are first (or only) posted as preprints. For comparison, one 2021 study (itself a preprint) reported that 4 percent of all scientific papers, not just those related to COVID, were preprints.

One preprint platform outlined the pros and cons of preprints, including that the lack of “expert assessment” can make it harder to judge the quality of a study. Because journalists and social media users often bring attention to particularly surprising preprint findings, weaker studies might receive undue attention, perhaps even more than stronger studies, in some cases. Specifically, “good work could be ignored over a weaker, more overblown study, leading to confusion and misinformation.” This platform recommended “tighter screening processes” for preprint platforms and education of the public on the distinction between preprint articles and peer-reviewed articles.

The Bottom Line for You, as You Read Science News

Increasingly, journalists specify the source of the scientific research on which they report, noting when they cite a preprint (although this research and this research suggest that this journalistic practice is far from universal). As good consumers of information, we should notice when the research is a preprint and take that into account as we form our own conclusions. If a news report about new research seems particularly surprising and the journalist didn’t mention details about the source, follow the link and see for yourself. A preprint will be clearly labeled as such. Understanding the difference between preprints and peer-reviewed articles is another critical-thinking tool in our information toolkit.

(And if you want to totally geek out, you can follow @preprintsifter, a Twitter tool that retweets discussions of COVID-related preprints.)