Peer review is considered crucial to the selection and publication of quality science, but very little is known about the previous experiences and training that might identify high-quality peer reviewers. The reviewer selection processes of most journals, and thus the qualifications of their reviewers, are ill defined. More objective selection of peer reviewers might improve the journal peer review process and thus the quality of published science.
Methods and Findings
306 experienced reviewers (71% of all those associated with a specialty journal) completed a survey of past training and experiences postulated to improve peer review skills. Reviewers performed 2,856 reviews of 1,484 separate manuscripts during a four-year study period, all prospectively rated on a standardized quality scale by editors. Multivariable analysis revealed that most variables, including academic rank, formal training in critical appraisal or statistics, or status as principal investigator of a grant, failed to predict performance of higher-quality reviews. The only significant predictors of quality were working in a university-operated hospital versus other teaching environment and relative youth (under ten years of experience after finishing training). Being on an editorial board and doing formal grant (study section) review were each predictors for only one of our two comparisons. However, the predictive power of all variables was weak.
Our study confirms that there are no easily identifiable types of formal training or experience that predict reviewer performance. Skill in scientific peer review may be as ill defined and hard to impart as is “common sense.” Without a better understanding of those skills, it seems unlikely journals and editors will be successful in systematically improving their selection of reviewers. This inability to predict performance makes it imperative that all but the smallest journals implement routine review ratings systems to routinely monitor the quality of their reviews (and thus the quality of the science they publish).
A survey of experienced reviewers, asked about training they had received in peer review, found there are no easily identifiable types of formal training and experience that predict reviewer performance.
When medical researchers have concluded their research and written it up, the next step is to get it published as an article in a journal, so that the findings can be circulated widely. These published findings help determine subsequent research and clinical use. The editors of reputable journals, including PLoS Medicine, have to decide whether the articles sent to them are of good quality and accurate and whether they will be of interest to the readers of their journal. To do this they need to obtain specialist advice, so they contact experts in the topic of the research article and ask them to write reports. This is the process of scientific peer review, and the experts who write such reports are known as “peer reviewers.” Although the editors make the final decision, the advice and criticism of these peer reviewers to the editors is essential in making decisions on publication, and usually in requiring authors to make changes to their manuscript. The contribution that peer reviewers have made to the article by the time it is finally published may, therefore, be quite considerable.
Although peer review is accepted as a key part of the process for the publishing of medical research, many people have argued that there are flaws in the system. For example, there may be an element of luck involved; one author might find their paper being reviewed by a reviewer who is biased against the approach they have adopted or who is a very critical person by nature, and another author may have the good fortune to have their work considered by someone who is much more favorably disposed toward their work. Some reviewers are more knowledgeable and thorough in their work than others. The editors of medical journals try to take in account such biases and quality factors in their choice of peer reviewers or when assessing the reviews. Some journals have run training courses for experts who review for them regularly to try to make the standard of peer review as high as possible.
Why Was This Study Done?
It is hard for journal editors to know who will make a good peer reviewer, and there is no proven system for choosing them. The authors of this study wanted to identify the previous experiences and training that make up the background of good peer reviewers and compare them with the quality of the reviews provided. This would help journal editors select good people for the task in future, and as a result will affect the quality of science they publish for readers, including other researchers.
What Did the Researchers Do and Find?
The authors contacted all the regular reviewers from one specialist journal (Annals of Emergency Medicine). A total of 306 of these experienced reviewers (71% of all those associated with the journal) completed a survey of past training and experiences that might be expected to improve peer review skills. These reviewers had done 2,856 reviews of 1,484 separate manuscripts during a four-year study period, and during this time the quality of the reviews had been rated by the journal's editors. Surprisingly, most variables, including academic rank, formal training in critical appraisal or statistics, or status as principal investigator of a grant, failed to predict performance of higher-quality reviews. The only significant predictors of quality were working in a university-operated hospital versus other teaching environment and relative youth (under ten years of experience after finishing training), and even these were only weak predictors.
What Do These Findings Mean?
This study suggest that there are no easily identifiable types of formal training or experience that predict peer reviewer performance, although it is clear that some reviewers (and reviews) are better than others. The authors suggest that it is essential therefore that journals routinely monitor the quality of reviews submitted to them to ensure they are getting good advice (a practice that is not universal).
Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0040040
• WAME is an association of editors from many countries who seek to foster international cooperation among editors of peer-reviewed medical journals
• The Fifth International Congress on Peer Review and Biomedical Publication is one of a series of conferences on peer review
• The PLoS Medicine guidelines for reviewers outline what we look for in a review
• The Council of Science Editors promotes ethical scientific publishing practices
• An editorial also published in this issue of PLoS Medicine discusses the peer review process further