RT Book, Section A1 Mark, Daniel B. A1 Wong, John B. A2 Loscalzo, Joseph A2 Fauci, Anthony A2 Kasper, Dennis A2 Hauser, Stephen A2 Longo, Dan A2 Jameson, J. Larry SR Print(0) ID 1190470639 T1 Decision-Making in Clinical Medicine T2 Harrison's Principles of Internal Medicine, 21e YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264268504 LK accessmedicine.mhmedical.com/content.aspx?aid=1190470639 RD 2024/03/28 AB Practicing medicine at its core requires making decisions. What makes medical practice so difficult is not only the specialized technical knowledge required but also the intrinsic uncertainty that surrounds each decision. Mastering the technical aspects of medicine alone, unfortunately, does not ensure a mastery of the practice of medicine. Sir William Osler’s familiar quote “Medicine is a science of uncertainty and an art of probability” captures well this complex duality. Although the science of medicine is often taught as if the mechanisms of the human body operate with Newtonian predictability, every aspect of medical practice is infused with an element of irreducible uncertainty that the clinician ignores at her peril. Although deeply rooted in science, more than 100 years after the practice of medicine took its modern form, it remains at its core a craft, to which individual doctors bring varying levels of skill and understanding. With the exponential growth in medical literature and other technical information and an ever-increasing number of testing and treatment options, twenty-first century physicians who seek excellence in their craft must master a more diverse and complex set of skills than any of the generations that preceded them. This chapter provides an introduction to three of the pillars upon which the craft of modern medicine rests: (1) expertise in clinical reasoning (what it is and how it can be developed); (2) rational diagnostic test use and interpretation; and (3) integration of the best available research evidence with clinical judgment in the care of individual patients (evidence-based medicine [EBM]).