Prefer positive results

In an earlier analysis, a group of researchers found that out of 74 studies of a particular antidepressant, 37 out of 38 submitted positive results were published, while only 3 of the 24 submitted negative studies were published. In addition, 8 submitted negative results were reformulated as positive for publication purposes. Studies with a negative result were thus only published at a tenth of a rate as the positive.

"In order to study the effect of the publication tendency (bias), we have used computer calculations to create a model for how a hypothesis can be perceived as true or false after repeated experiments based on previously published scientific articles on the hypothesis," explains Silas Boye Nissen, PhD student in biophysics at the Niels Bohr Institute at the University of Copenhagen.

The probability that a hypothesis is true or false moves up and down a 'ladder' as more and more experiments relating to the hypothesis are published.

Necessary negative results

"Our model shows that if not enough negative results are published then hypothesis that are actually false could be perceived as being true facts. If, however, you increase the rate (often in the order of 20-30 percent) at which negative results are published, it would be easier to distinguish false hypothesis from true facts," says Silas Boye Nissen, who made the calculations together with researchers at the University of Washington in Seattle, USA.

https://www.eurekalert.org/pub_releases/2016-12/uoc--sc121916.php