The purpose of clinical trials is to evaluate the safety and efficacy of treatment interventions such as drugs, devices and diagnostic tests. It is therefore essential for the safety of those receiving these interventions, as well as for scientific integrity, that these trials are conducted according to a protocol that is scientifically and ethically sound. The importance of a properly designed trial was recognised in the early years of modern clinical research as demonstrated by the works of Sir Ronald A Fisher in his Principles of experimental design in the 1920s.1 The first randomised trial in 1946 investigated the effectiveness of streptomycin for TB.2 Since then, the methodological rigour of clinical trials has continued to improve. Recent notable improvements include the prospective registration of trials (which is now a requirement for research ethics approval in the UK),3 efforts to improve trial protocols,4 standardisation of the definitions of interventions5 and outcomes,6 as well as improved reporting of clinical trials.7 More recently, in the setting of evidence that the reporting …