The randomized control trial (RCT) provides the strongest research design. A group of people are randomly allocated by the researcher to two or more groups. The experimental group receives the new treatment whereas the control group receives either conventional therapy, a placebo, or nothing. For example, our psoriasis patients would be split into two groups by the flip of a coin. The "heads" group would receive clam juice, and the "tails" group would receive a placebo concoction. Ideally, in order to minimize various biases, neither the patient nor the researcher knows who got what until the trial is over. This is referred to as being "double blind." (If the pharmacist who dispensed the stuff loses the code, it can be called either a "triple blind" or a disaster. In either case, the pharmacist's life is in jeopardy.) More than two groups can be used in an RCT as long as subjects are allocated by some randomizing device.
The major advantage of the RCT is that it ensures that there are no systematic differences between the groups. Because they originally are drawn at random from the same population, randomization ensures that they will be identical except for the differences that might arise from chance. In fact, the basis of many statistical tests of hypotheses is that the groups are drawn randomly from a population.
However, there are two major drawbacks to the RCT. The first is the cost. Some of the trials designed to look at the effect of aspirin on re-infarction rate cost between $3 and $7 million, and the most expensive one of all (at least until now), which was designed to look at lipids and infarction, costs $150 million US! The second major drawback is that patients who volunteer to participate in an RCT and who agree to allow the management of their disease to be decided by the flip of a coin may not be representative of patients in general.
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Do You Suffer From the Itching and Scaling of Psoriasis? Or the Chronic Agony of Psoriatic Arthritis? If so you are not ALONE! A whopping three percent of the world’s populations suffer from either condition! An incredible 56 million working hours are lost every year by psoriasis sufferers according to the National Psoriasis Foundation.