Consider the clinicaltrials by which drugs are tested in human subjects.5 Before a new drug can enter the market, its manufacturer must sponsor clinicaltrials to show the Food and Drug Administration that the drug is safe and effective, usually as compared with a placebo or dummy pill. The results of all the trials (there may be many) are submitted to the FDA, and if one or two trials are positive—that is, they show effectiveness without serious risk—the drug is usually approved, even if all the other trials are negative.