Randomized Controlled Trials 1948 – More Reliable Results

Designing tests to determine the effectiveness of a medical treatment can be surprisingly difficult for many reasons. For example, physicians may assess results in a biased and nonobjective way. Treatment effects may be uncertain, and patients may respond positively solely because of the placebo effect. The placebo effect works because patients think their condition has improved after receiving a sham "treatment" (such as an inert sugar pill).

Today, one of the most reliable approaches to testing potential medical treatments is the randomized controlled trial (Randomized Controlled Trials – RCTs). Random allocation gives each patient an equal chance of receiving each treatment being studied. RCTs may be double-blind, meaning that neither the principal investigators nor the patients know which patients are in the treatment group (receiving a new medicine) or the control group (receiving standard treatment). For ethical reasons, RCTs are generally conducted when researchers and physicians are genuinely uncertain about the preferred treatment.

The most famous early clinical study involving an RCT was British statistician Bradford Hill's "Streptomycin Treatment of Pulmonary Tuberculosis" . In this study, patients randomly selected the following cards:

• a sealed envelope containing a card marked "S" (streptomycin, an antibiotic, and bed rest) 
• an envelope containing a card marked "C" (bed rest alone).

The trial conclusively demonstrated that streptomycin was effective.

Clinical epidemiologist Murray Enkin: "This trial is rightly regarded as a landmark and the beginning of a new era in medicine. The [RCT] concept, which forms the foundation of evidence-based medicine, has justly been praised for the changes it brought to clinical decision-making."

Historical Figures Mentioned in This Article: Austin Bradford Hill (1897–1991)

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