How to appraise clinical trials

Treatment decisions should be based on reliable data. However, randomized controlled trials are susceptible to bias and other important limitations. Critical appraisal of such studies must consider both the methodological rigour of the study and the applicability of the results to routine clinical practice. Readers should work systematically through trial reports. They should establish the aims of the study and consider whether the methods used are able to provide an unbiased answer. Particular attention should be directed towards patient allocation, ensuring that the study groups are well balanced.