What is peer review?

Before they are published in an academic journal, scientific articles are usually vetted in a process called “peer review”. The journal’s editors send the manuscript to a handful of referees – other experts in the field who were not involved in the research. They look for weak points in its assumptions, methods, analyses and conclusions, and recommend changes. Once these have been done to the editors’ satisfaction, the article can be published.

The process is far from perfect, however. It is slow and opaque. Refereeing is often anonymous and referees are not paid for their work, so they have little incentive to be diligent. “Some of the worst papers ever went through the peer review system of the world’s top journals,” says Stuart Ritchie of Kings College London, a prominent critic of bad science. Or referees may belong to rival research teams, and hence have an incentive to scupper perfectly good research. There’s an adage that peer review eliminates the very worst papers but also the most original, and lets through a random selection of the rest.

Peer review goes back to the scientific revolution but has not stood still. One fairly recent innovation is the preprint. These are early drafts of scientific papers that are posted online, usually on dedicated websites called preprint servers. This allows for discussion, criticism and error checking in advance of the formal peer review process so, in theory at least, when the paper is submitted to a journal it is in better shape than its draft form.

The physical sciences and economics were the first to embrace preprints in the early 1990s but the practice has now spread across the board. The biomedical sciences were the last to join the revolution because of fears that dissemination of preliminary results of great public interest would lead to the spread of bad science, misinformation, rumours and unfounded health scares. It finally joined the revolution in 2019, just in time for covid-19. Those fears proved well-founded and the pandemic has been scarred by a parallel “” of bad science, misinformation, rumours , conspiracy theories and unfounded health scares.