statistical science has traveled a long distance. It is time that it is realized as a management science. This is especially true for biostatistics. I seek to define biostatistics as the science of managing medical uncertanities1. This can provide a completely new orientation to the subject and integrate it fully well into medical disciplines. How is this new definition justifiable? Health differs greatly from person to person and in the same person from time to time. The variations are so prominent that no two individuals have ever been exactly alike. Differences in facial features and morphologic appearance help us to identify people uniquely. But more important for medicine are the profound variations in physiologic functions. We all know that measurements such as hemoglobin level, cholesterol level, and heart rate differ from person to person even in perfect health. Variations occur not only between individuals but also within individuals from time to time. Diurnal variations in body temperature, blood pressure, and blood glucose levels are normal. In addition, states such as shock, anger, and excitement affect most of us temporarily but have the potential to produce long-term sequelae. In the presence of such large variation, it is not surprising that a response to a stimulus such as a drug can seldom be exactly reproduced even in the same person. Uncertainties resulting from these variations are an essential feature of the practice of medicine and deserve to be recognized.