Prologue

Everyone desires good health. Achieving this goal requires health care based on prevention, diagnosis, prognosis, treatment, and counseling. Maximum benefit from these activities depends on the accuracy of their scientific foundations. Precision1 depends on valid data. However, inherent in precision are both recognized and unexpected limitations. These characteristics constitute uncertainties that bedevil you and your health professionals alike. Uncertainty may be based on partial or even a lack of data. In these cases, uncertainty may be relieved when additional data are generated and interpreted. However, even when data exist, experts may disagree over their interpretation. Perhaps most frustrating is being told that uncertainty exists but that no one seems interested in studying it. However, shunning pessimism is crucial. In the words of the American civil rights champion Rev. Dr. Martin Luther King, Jr. (1929–1968), “Darkness cannot drive out darkness. Only light can do that” (King, 1998). All of us in health care must work collectively to flip on the switch.