Researchers at Northwestern University led by Drs. Diane Wayne, Jeff Barsuk and William McGaghie pioneered the use of mastery learning in the health professions. In 2006 they investigated mastery learning vs. traditional medical education in advanced cardiac life support techniques and showed that internal medicine resident trainees significantly improved adherence to American Heart Association protocols after mastery training. Subsequent investigations showed improved patient care practices as a result of this rigorous education including reduced patient complications and healthcare costs. These effects on patient care were seen in operating rooms, cardiac catheterization lab, intensive care units and patient floors at a large urban teaching hospital in Chicago. Further study also involved communication skills such as breaking bad news and end of life discussions, and patient self-management skills. In 2020 the Northwestern group published an important textbook entitled Mastery Learning in Health Professions Education. The approach designed by Northwestern investigators is currently in use at other health care institutions and medical schools throughout the US and the world.