When considering the eligibility of studies for inclusion in a Cochrane review, it is important to be aware that some studies may have been found to be fraudulent or may for other reasons have been retracted since publication. Reports of studies indexed in MEDLINE that have been retracted (as fraudulent or for other reasons) will have the Publication Type term ‘Retracted Publication’ added to the record. The article giving notice of the retraction will have the Publication Type term ‘Retraction of Publication’ assigned. Prior to any decision being taken to retract an article, articles may be published that refer to an original article and raise concerns of this sort. Such articles would be classified as a Comment. The US National Library of Medicine’s (NLM’s) policy on this is that “Among the types of articles that will be considered comments are: ….. announcements or notices that report questionable science or investigations of scientific misconduct (sometimes published as ‘Expression of concern’)”.
o www.nlm.nih.gov/pubs/factsheets/errata.html
In addition, articles may have been partially retracted, corrected through a published erratum or may have been corrected and re-published in full. When updating a review, it is important to search MEDLINE for the latest version of the citations to the records for the included studies. In some display formats of some versions of MEDLINE the retracted publication, erratum and comment statements are included in the citation data immediately after the title and are, therefore, highly visible. This is not, however, always the case so care should be taken to ensure that this information is always retrieved in all searches by downloading the appropriate fields together with the citation data (see Section 6.5.2). For further details of NLM’s policy and practice in this area see:
o www.nlm.nih.gov/pubs/factsheets/errata.html