There are special circumstances when similarity in text is expected in Cochrane Systematic Reviews by the nature of the type of work. These special circumstances may result in text similarity software, such as CrossCheck (Table 1), finding a high level of similarity of the Cochrane Review text with text from other article(s). High levels of similarity would not always be considered plagiarism.
Table 1. Special circumstances that will generate high levels of text similarity between Cochrane Systematic Reviews, versions of Cochrane Systematic Reviews, and other articles
Text similarity expected?
Similar methods sections
Yes, Cochrane Reviews can be expected to have a high percentage of overlap in the methods section because of standardized methods. This is unlikely to cause concern unless text is copied verbatim and without correct citation
Cochrane Review Group-specific template used for text in one or more sections
Yes, if an author uses a Cochrane Review Group template for one or more sections (e.g. background, methods), and states that a template has been used, a high percentage of overlap would be expected and should not cause concern
See ‘Use of text templates’ below for details
Protocol to review, review to update, etc.
Yes, a high percentage of overlap would be expected between certain sections of these versions (e.g. background, methods) and should not cause concern
Yes, a high percentage of overlap would be expected between certain sections of the protocol and the reviews that follow the protocol (e.g. background, methods). This should not cause concern, but it should be clear to the reader that the same text is used across a series of linked reviews
Split and merged reviews
Yes, some overlap would be expected between the different reviews. This should not cause concern, but it should be clear to the reader that the same text is used across a series of linked reviews
Similarities with published studies (e.g. trials described in the characteristics tables/risk of bias tables)
Yes, some overlap would be accepted here. Authors should follow the guidance (see ‘Avoiding plagiarism’) to avoid the possibility of plagiarism
Co-publication of a Cochrane Review (including Protocol and Updates) or republication in official Cochrane journals or derivative products
Yes, a high level of overlap would be expected. This should not cause concern as long as the co-publication was agreed according to the policy
A non-Cochrane systematic review is converted to a Cochrane Review
Yes, a high level of overlap may be expected. This should not cause concern as long as the co-publication was agreed according to the policy
A Cochrane Review is expected to be an original piece of academic work produced by the listed authors. Material copied from other sources may be used but should always be acknowledged. If direct quotes of more than a few words of original material are included, these should generally be indicated both by using quotation marks andby citing the source (citation alone is not enough). See examples in Table 2.
Table 2. Examples of correct citation
|Citing||The study was successful (Griffin 1990); it confirmed previous findings (Howes 1995).|
|Paraphrasing: using own words and making the source clear from the reference||It is the responsibility of systematic review authors to ensure the review conforms to Cochrane reporting guidelines including: declaring any potential conflicts of interest, that the review is free from plagiarised material and that all contributors are acknowledged (Wager 2011).|
|Using text verbatim||Wager and colleagues proposed that authors should “...ensure that contributors are properly acknowledged, that potential conflicts of interest are declared, and that the review does not contain plagiarized material” (Wager 2011).|