Editing Meta-analysis (section)

===Problems arising from agenda-driven bias===

The most severe fault in meta-analysis often occurs when the person or persons doing the meta-analysis have an [[economic]], [[Social issues|social]], or [[political]] agenda such as the passage or defeat of [[legislation]].<ref>{{Cite news |title=Research into trans medicine has been manipulated |url=https://www.economist.com/united-states/2024/06/27/research-into-trans-medicine-has-been-manipulated |access-date=2024-09-28 |newspaper=The Economist |issn=0013-0613}}</ref> People with these types of agendas may be more likely to abuse meta-analysis due to personal [[bias]]. For example, researchers favorable to the author's agenda are likely to have their studies [[Cherry picking (fallacy)|cherry-picked]] while those not favorable will be ignored or labeled as "not credible". In addition, the favored authors may themselves be biased or paid to produce results that support their overall political, social, or economic goals in ways such as selecting small favorable data sets and not incorporating larger unfavorable data sets. The influence of such biases on the results of a meta-analysis is possible because the methodology of meta-analysis is highly malleable.<ref name="Stegenga">{{cite journal | vauthors = Stegenga J | title = Is meta-analysis the platinum standard of evidence? | journal = Studies in History and Philosophy of Biological and Biomedical Sciences | volume = 42 | issue = 4 | pages = 497–507 | date = December 2011 | pmid = 22035723 | doi = 10.1016/j.shpsc.2011.07.003 | url = https://philpapers.org/rec/STEIMT | author-link = Stegenga J }}</ref>

A 2011 study done to disclose possible conflicts of interests in underlying research studies used for medical meta-analyses reviewed 29 meta-analyses and found that conflicts of interests in the studies underlying the meta-analyses were rarely disclosed. The 29 meta-analyses included 11 from general medicine journals, 15 from specialty medicine journals, and three from the [[Cochrane Database of Systematic Reviews]]. The 29 meta-analyses reviewed a total of 509 [[randomized controlled trials]] (RCTs). Of these, 318 RCTs reported funding sources, with 219 (69%) receiving funding from industry (i.e. one or more authors
having financial ties to the pharmaceutical industry). Of the 509 RCTs, 132 reported author conflict of interest disclosures, with 91 studies (69%) disclosing one or more authors having financial ties to industry. The information was, however, seldom reflected in the meta-analyses. Only two (7%) reported RCT funding sources and none reported RCT author-industry ties. The authors concluded "without acknowledgment of COI due to industry funding or author industry financial ties from RCTs included in meta-analyses, readers' understanding and appraisal of the evidence from the meta-analysis may be compromised."<ref>{{citation | title=Reporting of Conflicts of Interest in Meta-analyses of Trials of Pharmacological Treatments | journal = Journal of the American Medical Association | vauthors = Roseman M, Milette K, Bero LA, Coyne JC, Lexchin J, Turner EH, Thombs BD | volume = 305 | issue = 10 | pages = 1008–1017 | year = 2011 | doi = 10.1001/jama.2011.257 | pmid = 21386079 | url = https://www.rug.nl/research/portal/en/publications/reporting-of-conflicts-of-interest-in-metaanalyses-of-trials-of-pharmacological-treatments(d4a95ee2-429f-45a4-a917-d794ee954797).html | hdl = 11370/d4a95ee2-429f-45a4-a917-d794ee954797 | s2cid = 11270323 | hdl-access = free }}</ref>

For example, in 1998, a US federal judge found that the United States [[Environmental Protection Agency]] had abused the meta-analysis process to produce a study claiming cancer risks to non-smokers from environmental tobacco smoke (ETS) with the intent to influence policy makers to pass smoke-free–workplace laws.<ref>{{Cite journal |last=Spink |first=Paul |date=1999 |title=Challenging Environmental Tobacco Smoke in the Workplace |url=https://journals.sagepub.com/doi/10.1177/146145299900100402 |journal=Environmental Law Review |language=en |volume=1 |issue=4 |pages=243–265 |doi=10.1177/146145299900100402 |bibcode=1999EnvLR...1..243S |issn=1461-4529}}</ref><ref>{{Cite web |last=Will |first=George |date=1998-07-30 |title=Polluted by the anti-tobacco crusade |url=https://www.tampabay.com/archive/1998/07/30/polluted-by-the-anti-tobacco-crusade/ |access-date=2024-09-28 |website=Tampa Bay Times |language=en}}</ref><ref>{{Cite journal |last1=Nelson |first1=Jon P. |last2=Kennedy |first2=Peter E. |date=2009 |title=The Use (and Abuse) of Meta-Analysis in Environmental and Natural Resource Economics: An Assessment |url=https://link.springer.com/article/10.1007/s10640-008-9253-5 |journal=Environmental and Resource Economics |language=en |volume=42 |issue=3 |pages=345–377 |doi=10.1007/s10640-008-9253-5 |bibcode=2009EnREc..42..345N |issn=0924-6460}}</ref>