If you spend a lot of time hanging around at sceptical websites, you'll be aware that when evidence is demanded in support of a claim, it is usually demanded in the form of a peer-reviewed journal article. The suggestion is that peer review provides some sort of check on quality: any peer reviewed paper should meet a certain minimum standard. But is this really the case?
First of all, what does it mean to say that an article is peer reviewed? If an article is peer reviewed, it has been checked over by scientists who work in a similar field to the submitted article. A submitted article will usually be sent to two or three reviewers, who will each read the paper and submit a report to the journal editor. The editor will then decide whether the article merits publication.
On the face of it, this would seem to imply that certain standards are being met. But there is some evidence that this isn't necessarily the case. For example, this article (found via Ben Golacre's miniblog) suggests that in Chinese journals, only 5.9-7.7% of supposed randomised controlled trials reported in peer reviewed articles had adequate procedures for randomisation. A lack of adequate randomisation means that there is a good chance of introducing bias into your trial, and it ought to be one of the first things a reviewer would check. While the article specifically addresses trials published in Chinese journals, I don't think there's any compelling reason to think that things are dramatically different in what we laughingly call the west. Anecdotally, anyone who spends time wading through journals as part of their day job will be able to come up with several examples of utterly dreadful papers that should never have been published. This is without looking at pseudojournals, such as those that concentrate on complementary and alternative medicine, where articles on quackery are peer reviewed by other quacks.
So, if peer review can't tell you whether a trial described as randomised is in fact randomised, what can it tell you? Does it really act as any kind of guarantee of minimum quality? I would suggest not.
That is not to say that peer review is useless as it stands. In my fairly limited experience, papers that I have submitted have always been significantly improved by peer review. But surely there's a way of making peer review "fit for purpose", to use the current jargon?
This post was prompted by a discussion at the Bad Science forum, where the idea of applying industrial-style quality assurance to journal articles was raised. This would mean that there would be some sort of checklist that a reviewer would have to go through, and this would be checked to make sure it had been done. It would not be much use to do this informally; there would need to be some formal way of doing it.
In fact, this is not too far from what already happens, in many cases. I've just got a review back in which the reviewers have answered a series of yes/no questions (in addition to their more detailed written comments). For example, "Are the interpretations and conclusions sound and supported by the interpretation provided?", and "Is the paper logically organised?". For the example of trials published in Chinese journals above, there could be a question like "Is the methodology appropriate for testing the specified hypotheses?". Again, there would have to be some checks that this had been adequately done; this is really what the journal editor should be doing. At present, I think the role of the editor is often too weak. They do little more than send out and receive reviews. This is probably not surprising, given that editors are usually working more or less voluntarily and tend to have plenty of other things that they need to do. And it is not always the case: there are many excellent editors who make a lot of effort to engage with the papers they are handling, and the reviewer's comments on them. But if the role of editors were beefed up, such that they spend time formally checking that reviews have been carried out adequately, then peer review might actually provide the quality guarantee that we seem to think it should.
That might require actually paying editors and reviewers for their time. This would be a fairly radical step, but if it led to a professionalisation of the journal reviewing and editing process it would probably be a good thing. And if it led to a reduction in the number, and an increase in the quality, of papers published, that would not be a bad thing either.