Intervention Trials

Most causes of premature death are avoidable. This is true not only of infectious diseases but also a large proportion of cardiovascular diseases and cancer. A major goal of public health is to find the causes of disease in a population and then intervene to remove them. But before a large-scale public health intervention is carried out, its effectiveness should be evaluated. The randomized controlled trial is one of the most powerful tools available in epidemiology. When properly conducted and reported, it allows the evaluation of a disease risk factor that is free from bias and may also, with an appropriate design, give a quantitative estimate of the public health benefit that may be expected from an intervention.