 To comply with duty hour restrictions, residency programs have adopted various strategies including the creation of night float systems where residents are required to work multiple nights in a row. Reduced shift length has been associated with decreased medical errors, motor vehicle collisions, and percutaneous injuries.Surgical residents who transitioned to a night float system from 24-hour call every 3rd day reported reduced fatigue, more time for sleep and independent reading and increased family time, while nurses and patients reported improved communication and quality of patient care. In a pilot study of urology residents assigned to a 12-hour day shift Monday-Friday, 12-hour night float Sunday-Friday or 24-hour home call, actigraphy was used to measure total sleep time, sleep latency and depth of sleep. Night float did not impact total sleep time or quality of sleep. However, these studies did not establish the optimal shift duration 