This month over 100 medical journals around the world are inviting readers to send information on unpublished trials. This amnesty should have important benefits for patients. Why?

Reports of properly conducted randomised controlled trials are the foundation of effective health care, but many are not submitted for publication.^{1 2} This reduces the power of systematic reviews to detect moderate but clinically important treatment effects. Patients may thus be denied effective forms of health care. A second problem is that since trials that show more promising effects are more likely to be submitted, research syntheses can give misleading conclusions about effectiveness. Patients may thus be exposed to useless or even harmful treatments.³Finally, patients may be asked to participate in new studies designed to address questions that have already been answered.⁴

Trials go unreported for a myriad of reasons: it is well documented that trials with non-significant results are substantially less likely to be submitted for publication.¹ Sometimes recruiting participants takes longer than expected at the expense of time set aside for report writing; investigators may change jobs and work remain unfinished; or investigators may discover a recently published trial on the same topic and conclude that their own results are redundant. Editors must also take some responsibility: there is a limit to the number of reports we can publish. Many investigators regret not having published their results, and when contacted almost all are delighted to provide them.

Although amnesty means giving pardon, we hope that investigators will see this as an opportunity—namely, to make the results of previously unreported trials publicly accessible, thus having the potential to contribute to the scientific foundation of health care. We urge all investigators with unreported trial data to register their trials by returning a photocopy of the registration form shown below. We would like to register any unreported controlled trial, including trials that have only been published as an abstract.

Registration can be undertaken by anyone able to provide the registration information, even if they cannot provide the actual trial data. We expect a degree of duplicate registration. The information will be made available by listing the trial details on a web site and in other ways. If specific trial data are required, for example by those conducting systematic reviews, then the reviewer will be able to seek this information directly from the trialist. Some of the trials may be suitable for full publication, and the journal will be happy to consider these.

Medical editors are acutely aware of the trials and tribulations of research reporting. On this occasion, because of the serious implications of unreported research, we are trying to cleave the trials from the tribulations. We are confident of a good response.

Dickersin K, Min YI. NIH clinical trials and publication bias.On-line J Curr Clin Trials [serial online] 1993; 28 Apr: Doc No 50. Easterbrook PJ, Berlin JA, Gopalan R, Matthews DR. Publication bias in clinical research. Lancet1991;337:867-72. Egger M, Davey Smith G. Misleading meta-analysis.BMJ 1995;310:752-4. Savulescu J, Chalmers I, Blunt J. Are research ethics committees behaving unethically? Some suggestions for improving performance and accountability.BMJ 1996;313:1390-3.