Background: Studies that do not confirm their prior hypotheses, otherwise called "negative" studies, receive less interest from different parties including authors, editors and sponsors, and so, not to publish such studies is a common phenomenon. Opinions differ on whether or not this phenomenon introduces imprecision into the assessment of health research and care.
Objective: The current paper gives arguments against and in favor of publishing "negative" trials, and tries to give suggestions for a more balanced approach to this problem.
Results: Arguments against publishing "negative" trials include: we need not publish erroneously "negative" trials; we need not publish a "negative" study out of worry that the favored treatment is inferior; full-length reports of "negative" trials devaluate the quality of literature, because the data are usually not so important, and generally receive little interest from readers, and so, not to publish them is a more or less "natural" matter of course. Arguments in favor of publishing "negative" trials include: no report reduces the flow of information because "negative" trials provide at least some evidence and balance against the overwhelming power of positive data readily accepted for publication; no report violates the promise to patient participants; studies that do not confirm prior hypotheses are especially important; not-publishing leads to unnecessary repetition of research. Initially, trials were frequently "negative" not only due to lack of power but also due to inappropriate hypotheses and poor designs. Currently, this is less so, and the issue of selective reporting, therefore, needs to be reassessed. Suggestions for a more balanced approach to the problem of selective reporting might include: careful planning before the trial begins, reduces the chance of biased and erroneously "negative" trials; any trial, "positive" or "negative", provides probabilities rather than truths; this notion does not explain away publication bias but does make it less of a problem; "negative" trials may not be appropriate for general journals but very relevant to specialist journals as well as other organs of specialist groups; ethical committees and trial review boards should address the issue of publishing as part of their function.
Conclusion: Data from properly executed trials should routinely be made available. However, we should not forget that the empirical observations provided by clinical trials, are statistically tested, and that statistics are based merely on probabilities. It means that we must consider a more philosophical attitude to clinical trial evidence in terms of acceptance that scientific truths are rarely absolute.