The 2003 regulations limiting housestaff work hours have had a profound impact on residency training. Although clinical outcomes appear to be unaffected, faculty and residents have expressed concern that education has been harmed, and the regulations' effect on patient safety remains unclear. The Institute of Medicine's report bases its recommendations on the growing body of research linking clinician fatigue and error, and recommends eliminating extended-duration shifts (defined as more than 16 hours), increasing days off, and improving sleep hygiene by reducing night duty and providing more scheduled sleep breaks. The report estimates that approximately $1.7 billion would be required to hire additional staff to allow residency programs to adhere to these recommendations. A related editorial discusses the balance between patient safety, resident safety, and resident education that was central to the development of these recommendations.