This, I think, is the study the first poster meant, Ioannidis 2005, 'Why Most Published Research Findings Are False': http://www.plosmedicine.org/article/info%

This, I think, is the study the first poster meant, Ioannidis 2005, 'Why Most Published Research Findings Are False': http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.0020124 http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fj... It's quite a famous paper. Many rebuttals, comments, blog-posts etc, have been published, have a look at the comments on the PLOS site, I especially like this blog post summarizing more research: http://simplystatistics.org/2013/09/25/is-most-science-false-the-titans-weigh-in/ http://simplystatistics.org/2013/09/25/is-most-science-false... From the same author, here's a small overview of the discussion at the end of 2013: http://simplystatistics.org/2013/12/16/a-summary-of-the-evidence-that-most-published-research-is-false/ http://simplystatistics.org/2013/12/16/a-summary-of-the-evid... Quote on the Ioannidis paper: >Under assumptions about the way people perform these tests and report them it is possible to construct a universe where most published findings are false positive results. Important drawback: The paper contains no real data, it is purely based on conjecture and simulation.