"Why do kids born in the summer get diagnosed more often with A.D.H.D.? How are marathons harmful for your health, even when you're not running? What do surgeons and salesmen have in common? Which annual event made people 30 percent more likely to contract COVID-19? As a University of Chicago-trained economist and Harvard medical school professor and doctor, Anupam Jena is uniquely equipped to answer these questions. And as a critical care doctor at Massachusetts General who researches health care policy, Christopher Worsham confronts its impact on the hospital's sickest patients. In this singular work of science and medicine, Jena and Worsham work together to reveal the hidden side of medicine, and its effect on everyone that touches the health care system. Relying on ingeniously devised natural experiments-random events that unknowingly turn us into experimental subjects-Jena and Worsham do more than offer readers colorful stories. They help us see the way our health is shaped by forces invisible to the untrained eye. Do you choose the veteran doctor or the rookie? Do you take the appointment on Monday or on Friday? Do you get the procedure now or wait a week? These questions are rife with significance; their impact can be life changing. In a style that's animated and enlightening, this book empowers you to see past the white coat and find out what really makes medicine work-and how it could work better"--