ABSTRACT
During the past four decades, clinical trials have emerged as a means for quantitative appraisal of various human health related problems. In this evolution, clinical and environmental epidemiology, toxicology, biomedical and clinical sciences, as well as a variety of other public health disciplines, have merged to form an interdisciplinary field of research, invaded by some challenging statistical methodological issues. These clinical trials, generally motivated by the search for an answer to a medical or epidemiological question, vary in their scopes and objectives, and also in their biomedical or bioenvironmental undercurrents. They are quite likely to be engulfed with medical ethics, cost-benefit prospects, administrative protocols, and drug-market incentives, so that (statistical) decision making aspects are to be judged from a much broader perspective. The human reaction to drug reception, generally referred to as drug-response, is not always easy to assess.
Moreover, it reveals enormous variablity, mainly due to variations in human metabolism, and also due to a number of genetic, familial, and environmental factors which are yet to be fully appraised. Some of these environmental factors work in slow progression and are quite latent in nature. For that reason, precise quantitative formulations, in terms of mathematical models that are customarily used in physical and chemical studies, may not be feasible in clinical trials. Hence, standard biometric methodology may not suffice for clinical trials.
