ABSTRACT
The randomized controlled trial (RCT) is accepted as the best trial design for comparing two medical therapies. It is similar to the experiment performed bv the scientist in the research laboratory, in that it has a rigorous design to minimize random error and systematic error (bias) that otherwise might lead to incorrect con clusions or generalizations about the effectiveness o f a treatment. However, unlike the laboratory experiment, it is used to address issues of concern in the clinical domain. Thus, the subjects are human beings and the investigator is the clinician researcher. There are several essential components of the randomized controlled trial. First, subjects are randomly allocated to two groups, usually a treatment group (in which the new treatment is being tested) and a control group (in which the standard therapy or a placebo is administered). Thus, the control group is concurrent, and subjects are randomly allocated to the two groups. Second the interventions and follow-up are standardized and performed prospectively. Thus, hopefully, both groups are similar in all respects except for the interventions being studied. Not only does this guard against differences in variables known to be important, but it also ensures that there are no differences due to other factors that have not yet been identified or cannot be measured.
