Background:​ Journal editors are responsible for what they publish and therefore have a duty to correct the record if published work is found to be unreliable. One method for such correction is retraction of an article. Anecdotal evidence suggested a lack of consistency in journal policies and practices regarding retraction. In order to develop guidelines, we reviewed retractions in Medline to discover how and why articles were retracted.

Methods:​ We retrieved all available Medline retractions from 2005 to 2008 and a one-in-three random selection of those from 1988 to 2004. This yielded 312 retractions (from a total of 870). Details of the retraction including the reason for retraction were recorded by two investigators.

Results:​ Medline retractions have increased sharply since 1980 and currently represent 0.02% of included articles. Retractions were issued by authors (63%), editors (21%), journals (6%), publishers (2%) and institutions (1%). Reasons for retraction included honest error or non-replicable findings (40%), research misconduct (28%), redundant publication (17%) and unstated/unclear (5%). Some of the stated reasons might have been addressed by corrections.

Conclusions:​ Journals' retraction practices are not uniform. Some retractions fail to state the reason, and therefore fail to distinguish error from misconduct. We have used our findings to inform guidelines on retractions.