Most published scientific research papers are wrong, according to a new analysis. Assuming that the new paper is itself correct, problems with experimental and statistical methods mean that there is less than a 50% chance that the results of any randomly chosen scientific paper are true.

John Ioannidis, an epidemiologist at the University of Ioannina School of Medicine in Greece, says that small sample sizes, poor study design, researcher bias, and selective reporting and other problems combine to make most research findings false. But even large, well-designed studies are not always right, meaning that scientists and the public have to be wary of reported findings.

"We should accept that most research findings will be refuted. Some will be replicated and validated. The replication process is more important than the first discovery," Ioannidis says.

In the paper, Ioannidis does not show that any particular findings are false. Instead, he shows statistically how the many obstacles to getting research findings right combine to make most published research wrong.

[...] [CLB: The targeted readership, other researchers, understand this point generally. Publishing reserach results is expected to lead to discussion, further research on the hypothesis, and often refutation, with improved or modified hypotheses emerging. The problem arises from the media and laypersons use of published research. Media is likely to publish startling, 'newsworthy' results to make headlines. They don't include the rest of the scientific process. What's missing in the popular press: repeating the results, relating the results to other findings, systematic analysis and synthesis of the results, and taking sample-based results in a reliable way into an understanding of how these actually relate to the more general population.]