Meta-analysis
Meta-analysis is defined as "a quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine."[1]
A meta-analyses is a subset of systematic reviews in which the results of the studies are numerically pooled.
Factors associated with higher quality meta-analyses
Meta-analyses by the Cochrane Collaboration tend to be of higher quality.[2]
Individual data meta-analyses, in which the records from individual patients are pooled together into one dataset, tend to have more stable conclusions.[3]
Factors associated with lower quality meta-analyses
About a third of meta-analyses that happen to precede large randomized controlled trials will conflict with the results of the trial.[4]
Conflict of interest
Meta-analyses produced with a conflict of interest are more likely to interpret results as positive.[5]
Publication bias
Publication bias against negative studies may threaten the validity of meta-analyses that are positive and all the studies included within the meta-analysis are small.[6][7]
References
- ↑ National Library of Medicine. Meta-analysis. Retrieved on 2007-12-06.
- ↑ Olsen O, Middleton P, Ezzo J, et al (2001). "Quality of Cochrane reviews: assessment of sample from 1998". BMJ 323 (7317): 829–32. PMID 11597965. [e]
- ↑ Poynard T, Munteanu M, Ratziu V, et al (2002). "Truth survival in clinical research: an evidence-based requiem?". Ann. Intern. Med. 136 (12): 888–95. PMID 12069563. [e]
- ↑ LeLorier J, Grégoire G, Benhaddad A, Lapierre J, Derderian F (1997). "Discrepancies between meta-analyses and subsequent large randomized, controlled trials". N. Engl. J. Med. 337 (8): 536–42. PMID 9262498. [e]
- ↑ Veronica Yank, Drummond Rennie, and Lisa A Bero, “Financial ties and concordance between results and conclusions in meta-analyses: retrospective cohort study,” BMJ 335, no. 7631 (December 8, 2007), http://www.bmj.com/cgi/content/abstract/335/7631/1202 (accessed December 7, 2007).
- ↑ Sutton AJ, Duval SJ, Tweedie RL, Abrams KR, Jones DR (2000). "Empirical assessment of effect of publication bias on meta-analyses". BMJ 320 (7249): 1574–7. PMID 10845965. [e]
- ↑ Egger M, Davey Smith G, Schneider M, Minder C (1997). "Bias in meta-analysis detected by a simple, graphical test". BMJ 315 (7109): 629–34. PMID 9310563. [e]