Trial Registration: A Great Idea Switches From Ignored to Irresistible

In a recent article in JAMA on the registration of clinical trials,¹ Dickersin and I pointed out that, 30 years after the idea of registering trials had been proposed, 18 years after registration of trials at inception had been shown to eliminate publication bias, and despite the presence of numerous trial registers large and small, Manheimer and Anderson² were correct in stating that "No comprehensive system for tracking, organizing, and disseminating information about ongoing clinical trials currently exists." We described a profound confusion about even the most basic data from, or existence of, clinical trials. Only half of the million or so trials conducted over the past 56 years are likely to have been reported,¹ and of those reported, a substantial proportion did not appear in MEDLINE.