Doctors use vital signs as a relatively straightforward way to detect an illness or monitor a person’s health. Key ones include blood pressure, body temperature, breathing rate, and heart rate. A report from the newly christened National Academy of Medicine (formerly the Institute of Medicine) proposes using 15 “vital signs” to track how health care in the United States measures up. These include life expectancy, well-being, access to care, patient safety, evidence-based care, and others. Why bother creating such a list? Health care costs in the U.S. are the highest in the world, yet people in many countries that spend less on health care are in better health overall and have better health care outcomes. In order to improve the performance of health care, we need to measure how it is doing in a logical, sustainable way. These vital signs will help us answer questions about what we are doing well and where we must improve.