Five questions that need answering when considering the design of clinical trials

Timothy Clark, Hugh Davies, Ulrich Mansmann

Evidence suggests that research protocols often lack important information on study design, which hinders external review. The study protocol should provide an adequate explanation for why the proposed study methodology is appropriate for the question posed, why the study design is likely to answer the research question, and why it is the best approach. It is especially important that researchers explain why the treatment difference sought is worthwhile to patients, and they should reference consultations with the public and patient groups and existing literature. Moreover, the study design should be underpinned by a systematic review of the existing evidence, which should be included in the research protocol. The Health Research Authority in collaboration with partners has published guidance entitled 'Specific questions that need answering when considering the design of clinical trials'. The guidance will help those designing research and those reviewing it to address key issues.