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
Article Type Empirical
Article Subtype Cross-sectional survey/Methodological systematic review
First Author Country Switzerland
Aim To assess patterns of duplication in included studies in systematic reviews of analgesia published between 1989 and 2002. The authors focus on reviews where the systematic review authors identify duplicate publications within their reviews themselves.
Level of Investigation Descriptive
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.
Number of systematic reviews included 141
Number of eligible systematic reviews assessed 141
Treatment impacted No
Treatment impacted description
Interpretation impacted Not Applicable
Interpretation impacted description