Why do some retracted papers continue to be cited?

Perpetuation of retracted publications is an ongoing and even increasing problem in the scientific community. In addition to the direct distortion of scientific credibility, the use of retracted findings for interpretation und discussion in subsequent publications poses the risk of drawing false and, for example in medical research, even harmful conclusions. One major contributor to this development is that many authors are not aware of the retraction status of a paper they cite. COPE guidelines state that the retracted status should be indicated as clearly as possible, but this is definitely not true for many retracted publications. Likewise, databases do not consequently link retracted articles with the notice of retraction. Furthermore, many papers are deposit in the original, i.e. pre-retraction version on personal or institutional websites or online repositories. Similarly, printed stock files are obviously unaffected by a retraction. Clear identification of a retracted article using a watermark and in databases is a crucial step while incorporation of an electronic retraction check in reference management software and during the online submission is necessary to detect and avoid citing retracted literature. Solving this problem needs the close attention of everybody involved in the publishing process: authors, reviewers, and publishers.