THE INTRODUCTIONPeer review is at the heart of the processes of not just medical journals but of all of science. It is the method by which grants are allocated, papers published, academics promoted, and Nobel prizes won. Yet it is hard to define. It has until recently been unstudied. And its defects are easier to identify than its attributes. Yet it shows no sign of going away. Famously, it is compared with democracy: a system full of problems but the least worst we have.
But does peer review 'work' at all? A systematic review of all the available evidence on peer review concluded that 'the practice of peer review is based on faith in its effects, rather than on facts.' But the answer to the question on whether peer review works depends on the question 'What is peer review for?'
One answer is that it is a method to select the best grant applications for funding and the best papers to publish in a journal. It is hard to test this aim because there is no agreed definition of what constitutes a good paper or a good research proposal. Plus what is peer review to be tested against? Chance? Or a much simpler process?
THE EVIDENCEThe Scientist:
Too Many Submissions
Editors at high-impact journals are reporting that the number of submissions is increasing every year. Researchers, it seems, want to get their data into a limited number of pages, sometimes taking extra measures to boost their success. Lately, academia seems to place a higher value on the quality of the journals that accept researchers' data, rather than the quality of the data itself. In many countries, scientists are judged by how many papers they have published in top-tier journals; the more publications they rack up, the more funding they receive.
In fact, in a paper presented at the 2005 International Congress on Peer Review and Biomedical Publication, a prospective review of 1,107 manuscripts submitted to the Annals of Internal Medicine, British Medical Journal, and The Lancet in 2003 showed that many major changes to the text demanded by peer review included toning down the manuscript's conclusions and highlighting the paper's limitations. This study suggests that boosting findings may cause more problems by overburdening reviewers even further.
Indeed, an abundance of data from a range of journals suggests peer review does little to improve papers. In one 1998 experiment designed to test what peer review uncovers, researchers intentionally introduced eight errors into a research paper. More than 200 reviewers identified an average of only two errors. That same year, a paper in the Annals of Emergency Medicine showed that reviewers couldn't spot two-thirds of the major errors in a fake manuscript. In July 2005, an article in JAMA showed that among recent clinical research articles published in major journals, 16% of the reports showing an intervention was effective were contradicted by later findings, suggesting reviewers may have missed major flaws.
Journal of the Royal Society of Medicine:
Slow and Expensive
Many journals, even in the age of the internet, take more than a year to review and publish a paper. It is hard to get good data on the cost of peer review, particularly because reviewers are often not paid (the same, come to that, is true of many editors). Yet there is a substantial `opportunity cost', as economists call it, in that the time spent reviewing could be spent doing something more productive—like original research.
The cost of peer review has become important because of the open access movement, which hopes to make research freely available to everybody. With the current publishing model peer review is usually `free' to authors, and publishers make their money by charging institutions to access the material. One open access model is that authors will pay for peer review and the cost of posting their article on a website. So those offering or proposing this system have had to come up with a figure—which is currently between $500-$2500 per article. Those promoting the open access system calculate that at the moment the academic community pays about $5000 for access to a peer reviewed paper. (The $5000 is obviously paying for much more than peer review: it includes other editorial costs, distribution costs—expensive with paper—and a big chunk of profit for the publisher.) So there may be substantial financial gains to be had by academics if the model for publishing science changes.
There is an obvious irony in people charging for a process that is not proved to be effective, but that is how much the scientific community values its faith in peer review.
People have a great many fantasies about peer review, and one of the most powerful is that it is a highly objective, reliable, and consistent process. I regularly received letters from authors who were upset that the British Medical Journal (BMJ) rejected their paper and then published what they thought to be a much inferior paper on the same subject. Always they saw something underhand. They found it hard to accept that peer review is a subjective and, therefore, inconsistent process.
But it is probably unreasonable to expect it to be objective and consistent. If I ask people to rank painters like Titian, Tintoretto, Bellini, Carpaccio, and Veronese, I would never expect them to come up with the same order. A scientific study submitted to a medical journal may not be as complex a work as a Tintoretto altarpiece, but it is complex. Inevitably people will take different views on its strengths, weaknesses, and importance.
So, the evidence is that if reviewers are asked to give an opinion on whether or not a paper should be published they agree only slightly more than they would be expected to agree by chance. Stephen Lock when editor of the BMJ conducted a study in which he alone decided which of a consecutive series of papers submitted to the journal he would publish. He then let the papers go through the usual process. There was little difference between the papers he chose and those selected after the full process of peer review. This small study suggests that perhaps you do not need an elaborate process. Maybe a lone editor, thoroughly familiar with what the journal wants and knowledgeable about research methods, would be enough. But it would be a bold journal that stepped aside from the sacred path of peer review.
The evidence on whether there is bias in peer review against certain sorts of authors is conflicting, but there is strong evidence of bias against women in the process of awarding grants. The most famous piece of evidence on bias against authors comes from a study by DP Peters and SJ Ceci. They took 12 studies that came from prestigious institutions that had already been published in psychology journals. They retyped the papers, made minor changes to the titles, abstracts, and introductions but changed the authors' names and institutions. They invented institutions with names like the Tri-Valley Center for Human Potential. The papers were then resubmitted to the journals that had first published them. In only three cases did the journals realize that they had already published the paper, and eight of the remaining nine were rejected—not because of lack of originality but because of poor quality.
Peters and Ceci concluded that this was evidence of bias against authors from less prestigious institutions. This is known as the Matthew Effect: 'To those who have, shall be given; to those who have not shall be taken away even the little that they have.'
The editorial peer review process has been strongly biased against 'negative studies', i.e. studies that find an intervention does not work. It is also clear that authors often do not even bother to write up such studies. This matters because it biases the information base of medicine. It is easy to see why journals would be biased against negative studies. Journalistic values come into play. Who wants to read that a new treatment does not work? That's boring.
Some journals, including the BMJ, make it a condition of submission that the editors can ask for the raw data behind a study. We did so once or twice, only to discover that reviewing raw data is difficult, expensive, and time consuming. I cannot see journals moving beyond trust in any major way unless the whole scientific enterprise moves in that direction.
Another answer to the question of what is peer review for is that it is to improve the quality of papers published or research proposals that are funded. The systematic review found little evidence to support this, but again such studies are hampered by the lack of an agreed definition of a good study or a good research proposal.
Peer review might also be useful for detecting errors or fraud. At the BMJ we did several studies where we inserted major errors into papers that we then sent to many reviewers. Nobody ever spotted all of the errors. Some reviewers did not spot any, and most reviewers spotted only about a quarter. Peer review sometimes picks up fraud by chance, but generally it is not a reliable method for detecting fraud because it works on trust. A major question, which I will return to, is whether peer review and journals should cease to work on trust.
Even when scientists are motivated to promote the truth, their behaviour may be influenced, and even dominated, by information gleaned from their peers’ behaviour, rather than by their personal dispositions. This phenomenon, known as herding, subjects the scientific community to an inherent risk of converging on an incorrect answer and raises the possibility that, under certain conditions, science may not be self-correcting.
THE VERDICTSo we have little evidence on the effectiveness of peer review, but we have considerable evidence on its defects. In addition to being poor at detecting gross defects and almost useless for detecting fraud it is slow, expensive, profligate of academic time, highly subjective, something of a lottery, prone to bias, and easily abused [...] Nevertheless, it is likely to remain central to science and journals because there is no obvious alternative, and scientists and editors have a continuing belief in peer review. How odd that science should be rooted in belief.
The most important question with peer review is not whether to abandon it, but how to improve it. Many ideas have been advanced to do so, and an increasing number have been tested experimentally. The options include: standardizing procedures; opening up the process; blinding reviewers to the identity of authors; reviewing protocols; training reviewers; being more rigorous in selecting and deselecting reviewers; using electronic review; rewarding reviewers; providing detailed feedback to reviewers; using more checklists; or creating professional review agencies. It might be, however, that the best response would be to adopt a very quick and light form of peer review—and then let the broader world critique the paper or even perhaps rank it in the way that Amazon asks users to rank books and CDs.
» Slate: "Revise and Resubmit!"
» EuroScientist: Mentors, mates or metrics: what are the alternatives to peer review?
» Nature News Blog: "The new dilemma of online peer review: too many places to post?"
» Jefferson et al., 2002: "Effects of Editorial Peer Review: A Systematic Review"