Duty hour reform for trainees was undertaken to improve patient safety. However, experts have raised concerns that duty hour limits have reduced educational opportunities for trainees. This study randomized internal medicine residency programs to either standard duty hour rules from the Accreditation Council on Graduate Medical Education (ACGME) or less stringent policies that did not mandate the maximum shift length or time off between shifts. Investigators found that trainees in both groups spent similar amounts of time in direct patient care and educational activities, and scores on examinations did not differ. Interns in flexible duty hour programs reported worse well-being and educational satisfaction compared to those working within standard duty hours. As in a prior study of surgical training, program directors of flexible duty hour programs reported higher satisfaction with trainee education. These results may help allay concerns about detrimental effects of duty hour reform on graduate medical education. A PSNet perspective reviewed changes to the ACGME requirements to create flexibility for work hours within the maximum 80-hour workweek.