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The Rise and Fall of Peer Review

Adam Mastroianni at Experimental History (Substack)

Photo by charlesdeluvio / Unsplash

For the last 60 years or so, science has been running an experiment on itself. The experimental design wasn’t great; there was no randomization and no control group. Nobody was in charge, exactly, and nobody was really taking consistent measurements. And yet it was the most massive experiment ever run, and it included every scientist on Earth.

Most of those folks didn’t even realize they were in an experiment. Many of them, including me, weren’t born when the experiment started. If we had noticed what was going on, maybe we would have demanded a basic level of scientific rigor. Maybe nobody objected because the hypothesis seemed so obviously true: science will be better off if we have someone check every paper and reject the ones that don’t pass muster. They called it “peer review.”

This was a massive change. From antiquity to modernity, scientists wrote letters and circulated monographs, and the main barriers stopping them from communicating their findings were the cost of paper, postage, or a printing press, or on rare occasions, the cost of a visit from the Catholic Church. Scientific journals appeared in the 1600s, but they operated more like magazines or newsletters, and their processes of picking articles ranged from “we print whatever we get” to “the editor asks his friend what he thinks” to “the whole society votes.” Sometimes journals couldn’t get enough papers to publish, so editors had to go around begging their friends to submit manuscripts, or fill the space themselves. Scientific publishing remained a hodgepodge for centuries.

(Only one of Einstein’s papers was ever peer-reviewed, by the way, and he was so surprised and upset that he published his paper in a different journal instead.)

That all changed after World War II. Governments poured funding into research, and they convened “peer reviewers” to ensure they weren’t wasting their money on foolish proposals. That funding turned into a deluge of papers, and journals that previously struggled to fill their pages now struggled to pick which articles to print. Reviewing papers before publication, which was “quite rare” until the 1960s, became much more common. Then it became universal.

Now pretty much every journal uses outside experts to vet papers, and papers that don’t please reviewers get rejected. You can still write to your friends about your findings, but hiring committees and grant agencies act as if the only science that exists is the stuff published in peer-reviewed journals. This is the grand experiment we’ve been running for six decades.

The results are in. It failed.


Peer review was a huge, expensive intervention. By one estimate, scientists collectively spend 15,000 years reviewing papers every year. It can take months or years for a paper to wind its way through the review system, which is a big chunk of time when people are trying to do things like cure cancer and stop climate change. And universities fork over millions for access to peer-reviewed journals, even though much of the research is taxpayer-funded, and none of that money goes to the authors or the reviewers.

Huge interventions should have huge effects. If you drop $100 million on a school system, for instance, hopefully it will be clear in the end that you made students better off. If you show up a few years later and you’re like, “hey so how did my $100 million help this school system” and everybody’s like “uhh well we’re not sure it actually did anything and also we’re all really mad at you now,” you’d be really upset and embarrassed. Similarly, if peer review improved science, that should be pretty obvious, and we should be pretty upset and embarrassed if it didn’t.

It didn’t. In all sorts of different fields, research productivity has been flat or declining for decades, and peer review doesn’t seem to have changed that trend. New ideas are failing to displace older ones. Many peer-reviewed findings don’t replicate, and most of them may be straight-up false. When you ask scientists to rate 20th century discoveries in physics, medicine, and chemistry that won Nobel Prizes, they say the ones that came out before peer review are just as good or even better than the ones that came out afterward. In fact, you can’t even ask them to rate the Nobel Prize-winning discoveries from the 1990s and 2000s because there aren’t enough of them.

Of course, a lot of other stuff has changed since World War II. We did a terrible job running this experiment, so it’s all confounded. All we can say from these big trends is that we have no idea whether peer review helped, it might have hurt, it cost a ton, and the current state of the scientific literature is pretty abysmal. In this biz, we call this a total flop.

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