Different patterns of duplicate publication: an analysis of articles used in systematic reviews

Ref ID 517
First Author E. von Elm
Journal JAMA
Year Of Publishing 2004
URL https://jamanetwork.com/journals/jama/articlepdf/198260/joc31171.pdf
Keywords • Transparency
• Pain
• Error
Problem(s) • Data extraction errors and double counting
Number of systematic reviews included 141
Summary of Findings Authors of 40% of 141 systematic reviews acknowledged identification of duplicates. Data from 60 articles were published twice, data from 13 articles were published three times, data from 3 article were published four times, and data from 2 articles were published five times. 63% of the duplicates had no cross-reference at all, indicating a high level of covert duplication.
Did the article find that the problem(s) led to qualitative changes in interpretation of the results? N/A
Are the methods of the article described in enough detail to replicate the study? No