Appraising the trial literature: checking randomization, controls, and blinding

: The three essentials of any trial that has the potential to alter the practice of medicine are randomization, inclusion of a control, and the highest possible level of blinding. Spending a few moments reading the Methods Section will often provide information sufficient for the reader to perform a critical appraisal of the results of the clinical trial. A variety of factors encourage a positive result in any clinical trial. Randomization techniques produce uncertainty and should be viewed as techniques to prevent either patient or physician from acquiring advance knowledge as to which treatment assignment or allocation is about to occur. The control treatment is the drug, device, test, or procedure administered in a clinical trial that serves as the standard against which the test treatments are evaluated. Technically controls may be classified according to their place in time or the type of intervention offered. Blinding may occur at several levels. When reviewing a trial, the reader should discern whether blinding was achieved to the highest degree possible. Assuring onesself that the trial is of high standard is the first step towards implementing a change in the pattern of one's practice.