Moves to improve the conduct and reporting of clinical trials have gathered pace this year. One issue that the BMJ has long grappled with is what to do about protocols of trials, and we announce a new policy that begins in January 2005.

Medical research should begin with a protocol that details the hypothesis, objectives, and methodology to be used in the study. Ideally the study should not deviate from the protocol, but in reality it often does. Sometimes deviating from the protocol is unavoidable—for example, when new evidence is published independently during the trial which invalidates the specified outcome. In other instances, protocol deviation may represent …