WHAT IS the purpose of trial registration and why is it so important to the integrity of research? Clinical trial registration serves the following purposes. First, by preregistering the trials, the primary outcome (why do the study) and method (how to do the study) get disclosed to the public. This makes certain biases unlikely to interfere with the interpretation of the results. Second, preregistration prevents conscious or unconscious manipulation of the results. This protects the integrity of the study. Lastly, the trial registration process encourages the delineation of all the necessary steps from protocol construction to publication. This enables researchers to formally construct and complete a clinical trial. Overall, it is extremely important, both for the conduct and reliability of the clinical trial, that registration is completed before patient enrollment begins.