Reducing the residue of retractions in evidence synthesis: ways to minimise inappropriate citation and use of retracted data.

The incorporation of publications that have been retracted is a risk in reliable evidence synthesis. Retraction is an important mechanism for correcting the literature and protecting its integrity. Within the medical literature, the continued citation of retracted publications occurs for a variety of reasons. Recent evidence suggests that systematic reviews and meta-analyses often unwittingly cite retracted publications which, at least in some cases, may significantly impact quantitative effect estimates in meta-analyses. There is strong evidence that authors of systematic reviews and meta-analyses may be unaware of the retracted status of publications and treat them as if they are not retracted. These problems are difficult to address for several reasons: identifying retracted publications is important but logistically challenging; publications may be retracted while a review is in preparation or in press and problems with a publication may also be discovered after the evidence synthesis is published. We propose a set of concrete actions that stakeholders (eg, scientists, peer-reviewers, journal editors) might take in the near-term, and that research funders, citation management systems, and databases and search engines might take in the longer term to limit the impact of retracted primary studies on evidence syntheses.