Bjorn G. Publication is positively skewed. Nature Medicine 2008;14:1133
doi:10.1038/nm1108-1133b
The article reports the results of some investigations showing that positive results of clinical trials for drugs or devices have a higher chance of getting published in the medical literature than negative trials. This leads to a phenomenon called ‘positive publication bias’, a serious problem that can make a drug or device appear in the literature to be more effective than it really is. Experts suggest that the FDA Amendments Act of 2007 has improved transparency, because the law mandates that sponsors or primary investigators of clinical trials for approved drugs post a summary of their results in a national open-access database, but not every type of clinical trial is covered by the legislation, nor does it directly affect medical journals.
http://www.nature.com/nm/journal/v14/n11/full/nm1108-1133b.html