Funding source predicts outcome. A Cochrane review of 75 studies found manufacturer-sponsored drug and device studies report favourable efficacy results and conclusions more often than independently funded ones, a gap that standard risk-of-bias checks do not explain. The routes are documented: negative trials left unpublished (Turner 2008), comparators chosen to win (Heres 2006, Flacco 2015) and conclusions that run ahead of the data (Als-Nielsen 2003). Sponsored trials are often well blinded, so they are not worthless; they need independent replication.
Summary drafted from this entry’s sources; editorial review pending.
01Key questions
Do industry-funded trials really get different results?
On average, yes. Lundh and colleagues pooled 75 studies and found sponsored drug and device studies more often had favourable efficacy results (risk ratio 1.27) and favourable conclusions (risk ratio 1.34) than studies with other funding.1
Does that mean sponsored trials are fake?
No. The same Cochrane review found sponsored trials were more often adequately blinded and no worse on randomisation or follow-up. The bias sits in what gets published, which comparison is run and how results are framed, so a sponsored positive result needs an independent replication.15
How much does unpublished data distort the picture?
In 74 FDA-registered antidepressant trials, 94% looked positive in the journals but only 51% were positive in the FDA's own analysis, and the published effect size was inflated by 32% overall.5
Does this apply to supplements and diets too?
Yes. Any company testing its own product has the same incentives. This site lists the payer for favourable and unfavourable studies alike, including diet companies and supplement makers, and documents the food industry's record on the sugar papers page.
What should a reader check in a sponsored study?
Check the registry for the pre-specified outcome, look at the comparator and dose, prefer hard outcomes over surrogates, read the results before the conclusion, and look for an independent replication. Ties to one company predicted favourable conclusions, not favourable results, in blood-pressure meta-analyses.10
Who pays for a study changes what it finds and, even more, what it concludes. A Cochrane methodology review of 75 studies found that drug and device trials paid for by the manufacturer report favourable efficacy results and favourable conclusions more often than trials funded from other sources, and that the usual risk-of-bias checks do not explain the gap. Unpublished negative trials, sponsor-chosen comparators and conclusions that run ahead of the data all feed it. None of this makes sponsored trials worthless: they are often better blinded than independent ones. It means a sponsored result needs an independent replication before it settles anything, and the same rule applies to supplement makers, diet companies and anyone else selling the thing being tested.
02What the meta-research shows
The question has been studied directly, many times, with the same answer.
- Cochrane, 75 studies. Lundh and colleagues pooled every study that compared industry-sponsored drug and device research with research funded from other sources. Sponsored studies more often had favourable efficacy results (risk ratio 1.27) and favourable conclusions (risk ratio 1.34), and their conclusions agreed with their own results less often. Sponsored trials did not score worse on randomisation, allocation concealment, follow-up or selective outcome reporting, and they were more often adequately blinded. The authors concluded there is "an industry bias that cannot be explained by standard 'Risk of bias' assessments" (Lundh 2017, PMID 28207928).
- Same data, different conclusion. In 370 randomised drug trials drawn from Cochrane meta-analyses, the experimental drug was recommended as treatment of choice in 16% of trials funded by non-profits and 51% of trials funded by for-profit organisations. After adjusting for the actual treatment effect, adverse events and trial quality, for-profit funding still predicted a recommendation (odds ratio 5.3). The authors' reading: the conclusions were more positive than the results justified (Als-Nielsen 2003, PMID 12928469).
- Investigators' own money. In 195 drug-efficacy trials published in core clinical journals in 2013, 58% of principal investigators had financial ties to the drug's maker. Ties were present in 76% of positive trials and 49% of negative ones, and a tie predicted a positive result even after adjusting for who funded the trial (odds ratio 3.57) (Ahn 2017, PMID 28096109).
- Older pooled evidence. A 2003 systematic review in JAMA pooled studies of industry sponsorship and found an odds ratio of 3.60 for pro-industry conclusions, along with more restrictions on publication and data sharing (Bekelman 2003, PMID 12533125).
03How the skew gets in
Trials that never appear
The cleanest demonstration used the FDA's own files. Turner and colleagues matched 74 antidepressant trials registered with the FDA against the journals. Of 38 trials the FDA judged positive, 37 were published. Of the trials the FDA judged negative or questionable, 22 were never published and 11 were published in a way that conveyed a positive outcome. Read through the journals, 94% of trials looked positive; in the FDA data, 51% were. The published literature overstated the drugs' effect size by 32% overall (Turner 2008, PMID 18199864). The authors could not say whether sponsors, authors or journals held the negative trials back.
The law now requires many US trials to post results on ClinicalTrials.gov within a year of completion. In the first audit of that rule, only 40.9% of 4,209 due trials reported on time. Industry sponsors complied more often than non-industry, non-government sponsors such as universities (DeVito 2020, PMID 31958402). Missing results are a system problem, not only an industry one.
Choosing the fight you win
Head-to-head trials are where sponsors pick comparator, dose and population. In 33 company-funded head-to-head trials of second-generation antipsychotics, 90% reported an overall result favouring the sponsor's drug, so that olanzapine beat risperidone, risperidone beat quetiapine and quetiapine beat olanzapine, depending on who paid (Heres 2006, PMID 16449469). Across 319 head-to-head trials published in 2011, industry funded most of them, and 55 of 57 industry-funded non-inferiority or equivalence trials got the result the sponsor wanted (Flacco 2015, PMID 25748073). In 192 statin comparison trials, funding from the test drug's maker was associated with results (odds ratio 20) and conclusions (odds ratio 35) favouring that drug, and 98% of the trials measured only surrogate outcomes such as cholesterol (Bero 2007, PMID 17550302).
Spin in the conclusions
Results can be honest while the abstract is not. In 124 meta-analyses of blood-pressure drugs, ties to a single drug company did not predict favourable results but did predict favourable conclusions (odds ratio 5.11) (Yank 2007, PMID 18024482). Read the results table before the conclusion.
04Why this cuts both ways
The same mechanics apply to anyone with a product. On this site's own pages, Virta Health funded its ketogenic-diet trial and its researchers held stock options (ketogenic approaches); Amazentis funded the urolithin A trials (urolithin A); and the main GLP-1 drug trials cited there were funded by Novo Nordisk and Eli Lilly (GLP-1 drugs). We show the payer for favourable and unfavourable studies alike in each page's "Who paid, and how it got here" box. Food and drink companies follow the same pattern: see the sugar papers.
The bias also has a flip side the official line rarely mentions. Trials cost money, and money follows patents. A cheap, off-patent compound rarely gets a large trial, so "no good trial" often means "no one paid", not "it was tested and failed". The absence of sponsored evidence is not evidence of failure, and the presence of sponsored evidence is not proof of success.
05How we read a sponsored study
- Find the funding statement and the authors' disclosures, then look the trial up in its registry and compare the registered primary outcome with the one reported.
- Check the comparator and the dose: a rival drug at a low dose, or a placebo when a standard treatment exists, tilts the field.
- Prefer hard outcomes (death, fractures, heart attacks) over surrogates (cholesterol, a biomarker) when a sponsor is selling the surrogate story.
- Read the numbers before the abstract's conclusion.
- Look for an independent replication. One sponsored positive trial is a lead, not a verdict.
This page describes research practice; it is not medical advice.
06Who paid, and how it got here
Who funded the key studies on this page, the favourable and the unfavourable alike, and how its legal status came about. From each paper’s funding and conflict-of-interest statements, trial registries and official documents; checked 1 Nov 2026. Why we show this
Who paid for the key studies
- Ahn 2017, cross-sectional study of 195 drug trialsInvestigator ties to the maker predicted positive results.Funding and interests: NCI (public funding); authors declared no industry ties. PubMed funding record
07Connections
08Sources
- Lundh A, Lexchin J, Mintzes B, Schroll JB, Bero L. Industry sponsorship and research outcome. Cochrane Database Syst Rev. 2017;2:MR000033. PMID 28207928PubMed 28207928
- Als-Nielsen B, Chen W, Gluud C, Kjaergard LL. Association of funding and conclusions in randomized drug trials. JAMA. 2003;290(7):921-8. PMID 12928469PubMed 12928469
- Ahn R, Woodbridge A, Abraham A et al. Financial ties of principal investigators and randomized controlled trial outcomes. BMJ. 2017;356:i6770. PMID 28096109PubMed 28096109
- Bekelman JE, Li Y, Gross CP. Scope and impact of financial conflicts of interest in biomedical research. JAMA. 2003;289(4):454-65. PMID 12533125PubMed 12533125
- Turner EH, Matthews AM, Linardatos E, Tell RA, Rosenthal R. Selective publication of antidepressant trials and its influence on apparent efficacy. N Engl J Med. 2008;358(3):252-60. PMID 18199864PubMed 18199864
- DeVito NJ, Bacon S, Goldacre B. Compliance with legal requirement to report clinical trial results on ClinicalTrials.gov. Lancet. 2020;395(10221):361-369. PMID 31958402PubMed 31958402
- Heres S, Davis J, Maino K et al. Why olanzapine beats risperidone, risperidone beats quetiapine, and quetiapine beats olanzapine. Am J Psychiatry. 2006;163(2):185-94. PMID 16449469PubMed 16449469
- Flacco ME, Manzoli L, Boccia S et al. Head-to-head randomized trials are mostly industry sponsored and almost always favor the industry sponsor. J Clin Epidemiol. 2015;68(7):811-20. PMID 25748073PubMed 25748073
- Bero L, Oostvogel F, Bacchetti P, Lee K. Factors associated with findings of published trials of drug-drug comparisons: why some statins appear more efficacious than others. PLoS Med. 2007;4(6):e184. PMID 17550302PubMed 17550302
- Yank V, Rennie D, Bero LA. Financial ties and concordance between results and conclusions in meta-analyses. BMJ. 2007;335(7631):1202-5. PMID 18024482PubMed 18024482
09Entry history
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