Decision making is a critical element in the field of medicine that can lead to life-or-death outcomes, yet it is an element fraught with complex and conflicting variables, diagnostic and therapeutic uncertainties, patient preferences and values, and costs. Together, decisions made by physicians, patients, insurers, and policymakers determine the quality of health care, quality that depends inherently on counterbalancing risks and benefits and competing objectives such as maximizing life expectancy versus optimizing quality of life or quality of care versus economic realities. Broadly speaking, concepts in medical decision making (MDM) may be divided into two m ..