Peer review: It's the bedrock of reputable scientific publishing. The idea is that if a study has been carefully examined and approved by another researcher in the same field, then it's valid enough to publish in a respected journal. But that idea only holds if the peer review system itself is trustworthy.
Hynung-In Moon, a medicinal-plant researcher at a university in South Korea, was having good luck with the reviews of the studies he was publishing in "The Journal of Enzyme Inhibition and Medicinal Chemistry." Aside from a few suggestions about how to improve his papers, they were quickly approved. Very quickly. In fact, the peer reviews were sometimes coming back to the editor of the journal within 24 hours of his having sent them out.
Growing suspicious, the editor asked Moon what was going on. The researcher fessed up — those fast, approving reviews were coming from none other than himself. Following common practice, the journal had asked Moon to suggest some potential reviewers. When he did, he gave them a combination of real and fictitious names with fake contact information, including email addresses that came to Moon's inbox [source: Ferguson et al].
It turns out that some of the systems set up for reviewing have a loopholes like this, and Moon's instance of self-review is not an isolated anomaly. This leaves us with the possibility that some of the peer-reviewed studies we hear about might actually be peer-less.