"Negative results have never made riveting reading," a 1987 editorialist in the British Medical Journal observed.
Nor have clinical research careers been much advanced through their publication. Perhaps its not surprising, then, that several studies have demonstrated the existence of publication bias. Around 20% of studies never have their results published or presented publicly, and of those appearing as meeting abstracts, half are never published in a peer-reviewed journal, said Chris Williams, M.D., coordinator of the Cochrane Cancer Network, Oxford, England.
"There is a strong link between failure to publish and a study being negative," he said. "At every level the bias in the literature favors seeing things in more of a rosy light than is perhaps true. So there is an in-built potential in meta-analysis to inflate benefit." Studies with significant positive results are published on average several years sooner than negative studies, and are more likely to appear in prestigious, high-profile journals.
But it would be unfair to lay the blame on journal editors rejecting negative studies, as a meta-analysis in the Dec. 31, 1993, Annals of the New York Academy of Sciences showed. In that analysis, covering 997 studies, Kay Dickersin, Ph.D., then of the University of Maryland, Baltimore, and now of Brown University, Providence, R.I., found that trials with statistically nonsignificant results were far more likely to go unpublished, with the trend even stronger for controlled trials and strongest for randomized trials.
"In every case, failure to publish was investigator-based, and not due to editorial decisions," she wrote. "Development of registration systems for randomized trials is essential if this problem is to be minimized in future."
Current Controlled Trials Ltd., of London, who have created the new metaRegister of Controlled Trials (see main article) plan to launch a series of peer-reviewed journals that will explicitly strive to avoid publication bias. The first, Current Controlled Trials in Cardiovascular Medicine, is now in development, with additional titles, including one on cancer, envisioned further down the road, said managing director Anne Greenwood.
"Our criteria for acceptance will be based on the quality of the trial, not the newsworthiness of the results," she said. The journals will take advantage of the Internets vast capacity to include detailed protocols and trial results that traditionally are not included in the print editions because of space restrictions.
Still, if investigators fail to submit negative results, journals cant be expected to drag the information out of them. But if prospective registration becomes the norm, meta-analysts and others looking for the big picture will at least know where to find out what happened to those disappearing trials.
![]() |
||||
|
Oxford University Press Privacy Policy and Legal Statement |