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2. LikeDislikeJohn Ioannidis and the Replication CrisisJohn Ioannidis is one of the most prominent voices in the discussion of the replication crisis in science. His 2005 essay “Why Most Published Research Findings Are False” remains one of the most cited and viewed scientific articles in history, with over 3 million views on PLOS Medicine IAI TV+1. In it, Ioannidis used statistical modeling to argue that many published results—especially in medical and biomedical research—are likely false positives due to factors like small study sizes, low statistical power, high flexibility in study designs, and selective reporting journals.plos.org.Core ArgumentsIoannidis showed that the positive predictive value (PPV)—the probability that a statistically significant result is actually true—can be low if the prior probability of a true effect is small, even with a low false-positive rate (e.g., α = 0.05) and moderate power (β = 0.2) Wikipedia. He identified key conditions that increase the likelihood of false findings:
   • Small effect sizes
   • Fewer true relationships tested relative to the number of hypotheses
   • High flexibility in definitions, outcomes, and analyses
   • Strong financial or institutional incentives
   • Large numbers of competing research teams journals.plos.org
   He also noted that many published findings may simply be accurate measures of the prevailing bias in a field journals.plos.org.Broader ImpactIoannidis’ work helped frame the replication crisis as a systemic issue, not just a problem in individual studies. It has influenced debates in medicine, psychology, public health, and beyond, prompting calls for:
   • More rigorous study design and reporting
   • Pre-registration of studies
   • Greater transparency in data and methods
   • Independent replication efforts
   • Meta-research to assess reproducibility Statistical Horizons
   Current ContextIn recent years, Ioannidis has continued to speak and write about the need for epistemic humility—acknowledging uncertainty and improving standards of evidence—especially when science informs public policy pcopelanwrites.com. He has also explored the role of meta-science in diagnosing and addressing structural problems in research Statistical Horizons.In summary: Ioannidis’ replication work is a cornerstone of modern metascience, highlighting that statistical misuse, bias, and methodological weaknesses can make most published findings unreliable, and advocating for systemic reforms to restore trust in scientific knowledge.Read lessIAI TVReason, replication and reality with John Ioannidishttps://iai.tv/video/reason-replication-and-reality-with-john-ioannidisjournals.plos.orgWhy Most Published Research Findings Are False – PLOShttps://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124Show All

1. pcopelanwrites.comhttps://pcopelanwrites.com › dr-john-ioannidis-on-replication-failure-and…Dr. John Ioannidis on replication failure and shaken trust in scienceJul 26, 2025 · John Ioannidis is Professor of Medicine, Epidemiology and Population Health at Stanford University. His landmark 2005 …
2. Videos of John Ioannidis Replication30:50The future of science and the replication crisis with John Ioannidis and Sandro GaleaYouTubeComplicating The Narrative19 views1 month ago56:12Is Reproducible Research Accurate? | John Ioannidis | Talks at GoogleYouTubeTalks at Google54.2K viewsJun 12, 201413:08The reproducibility crisis and other problems in science | John IoannidisYouTubeThe Institute of Art and Ideas14.7K viewsNov 26, 2024
3. Wikipediahttps://en.wikipedia.org › wiki › Why_Most_Published…Why Most Published Research Findings Are False – Wikipedia
   • Overview
   • Argument
   • Reception
   • Causes of high false positive rate
   • Further reading
   • External links
   “Why Most Published Research Findings Are False” is a 2005 essay written by John Ioannidis, a professor at the Stanford School of Medicine, and published in PLOS Medicine. It is considered foundational to the field of metascience.
   In the paper, Ioannidis argued that a large number, if not the majority, of published medical research papers contain results that cannot be replicated. In simple terms, th…Wikipedia · Text under CC-BY-SA license
4. Statistical Horizonshttps://statisticalhorizons.com › seminars › …Replication Crisis & Solutions | Online Course | Statistical HorizonsIn this seminar, Professor John P. A. Ioannidis will explore the factors that undermine reproducibility and research utility, including …
5. Statistical Horizonshttps://statisticalhorizons.com › … › john-p-a-ioannidisJohn P. A. Ioannidis | Research ReproducibilityJohn P. A. Ioannidis, Ph.D., teaches the live, online course Reproducible and Useful Research: The …
6. plos.orghttps://journals.plos.org › plosmedicine › articleWhy Most Published Research Findings Are False – PLOSAug 30, 2005 · Published research findings are sometimes refuted by subsequent evidence, says Ioannidis, with ensuing confusion …
7. IAI TVhttps://iai.tv › video › reason-replication-and…Reason, replication and reality with John IoannidisAug 5, 2025 · In 2005, John Ioannidis published an essay titled “Why Most Published Research Findings Are …
8. Wikipediahttps://en.wikipedia.org › wiki › John_IoannidisJohn Ioannidis – WikipediaIoannidis studies scientific research itself (meta-research) primarily in clinical medicine and the social sciences. He has served on the …
9. yale.eduhttps://bioethics.yale.edu › sites › default › files › files › Ioannidis.pdf^[PDF]Empirical Evidence on Reproducibility of Research John P.A.ished Research Findings Are False,” is the most-downloaded technical paper from PLoS Medicine. Ioannidis has published numerous …
10. Berliner Institut für Gesundheitsforschunghttps://www.bihealth.org › en › noticesReplication crisis: a 2005-2022 retrospective and future prospectsJun 30, 2022 · Talk of Prof. John Ioannidis, Einstein Visiting Fellow at BIH QUEST Center. Reviews of 17 years of research on the …
11. atticusli.comhttps://atticusli.com › replication-crisisIoannidis 2005: “Why Most Published Research Findings Are False …May 25, 2026 · The replication crisis as a contemporary phenomenon — the recognition that large fractions of published findings in …
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