Appraisal of: Golder S, Loke YK, Bland M. Unpublished data can be of value in systematic reviews of adverse effects: methodological overview. J Clin Epidemiol 2010;63(10):1071-1081.

Short description: 
The authors assessed the impact of including unpublished data on adverse effects in systematic reviews. They carried out a systematic review of methodological evaluations comparing the quantitative reporting of adverse effects data between published and unpublished sources. The key finding was that unpublished studies could provide additional adverse effects information. However, there was insufficient data to conclude whether including unpublished studies would have major impact on the results of meta-analyses.
Limitations stated by the author(s): 
Methodological evaluations are difficult to retrieve by database searches and it is possible that review articles may have been missed. There is also a possibility of reporting or publication bias with respect to methodological evaluations, as investigators may have chosen not to report their findings if they did not find any significant differences between published and unpublished studies.
Limitations stated by the reviewer(s): 
No additional limitations detected by the reviewer.
Study Type: 
Review
Related Chapters: 

Comments from the authors:

This publication is related to Su Golder’s PhD Thesis “Evaluating and Optimising the Retrieval of Research Evidence for Systematic Reviews of Adverse Drug Effects and Adverse Drug Reactions” from 2013. The thesis is available from http://etheses.whiterose.ac.uk/4749/