Objective: To determine whether poor reporting of methods in randomised controlled trials reflects on poor methods.
Design: Observational study.
Setting: Reports of randomised controlled trials conducted by the Radiation Therapy Oncology Group since its establishment in 1968.
Participants: The Radiation Therapy Oncology Group. Outcome measures Content of reports compared with the design features described in the protocols for all randomised controlled trials.
Results: The methodological quality of 56 randomised controlled trials was better than reported. Adequate allocation concealment was achieved in all trials but reported in only 42% of papers. An intention to treat analysis was done in 83% of trials but reported in only 69% of papers. The sample size calculation was performed in 76% of the studies, but reported in only 16% of papers. End points were clearly defined and alpha and beta errors were prespecified in 76% and 74% of the trials, respectively, but only reported in 10% of the papers. The one exception was the description of drop outs, where the frequency of reporting was similar to that contained in the original statistical files of the Radiation Therapy Oncology Group.
Conclusions: The reporting of methodological aspects of randomised controlled trials does not necessarily reflect the conduct of the trial. Reviewing research protocols and contacting trialists for more information may improve quality assessment.