A plea is made for wide concern among physicians for the relatively simple methods of examining the efficacy of new drugs in patients. A distinction must be made between examining of the individual patient and statistical proof from large series. The latter, the process of systematic verification, is generally so difficult, tedious, and slow as to discourage hopes for development of a rational drug therapy. The alternative process, thoughtful observation combined with clinical intuition, has led to important developments in the past and should not be neglected. The mutual interaction of these 2 processes is essential to the advancement of therapeutics.
Greiner T. Why We Rarely Know About Drugs. JAMA. 1961;177(1):42–45. doi:10.1001/jama.1961.73040270029004e