The long running campaign for comprehensive registration of clinical trials has taken a turn for the better. Over the past two years discussions have shifted from whether ongoing trials should be registered at all to detailed negotiations with the drugs and devices industries about what information should be registered for which trials and when.

Next week, at a meeting in Brussels to launch international clinical trials day—20 May, the same day as, in 1743, James Lind started his landmark trial of lime juice for scurvy—a landmark of similar historical importance could be struck: the setting of a tough international standard for disclosure of information about trials. Whether it happens or not will depend on the steadfastness of a small group at the World Health Organization.

Since the first calls for a comprehensive registry of clinical trials 30 years ago,^w1 journal editors^w2 and others^w3 have argued repeatedly for trial registration. Some enlightened drug companies have declared their support,^w4 laws have been passed,^w5 and trial registries have been set up, most notably clinicaltrials.gov at the US National Institutes of Health and the metaRegister of Clinical Trials established by Current Science Group in the United Kingdom. But despite these efforts, real progress has been hard to detect.

Barriers to trial registration, as characterised by Dickersin and Rennie in 2003, include industry resistance, lack …