http://healthland.time.com/2013/03/26/fewer-hours-for-doctors-in-training-leading-to-more-mistakes/

Although physician interns and residents are putting in shorter hours, their workload has not been reduced. Thus, they see more patients in a shorter period of time than ever before, leading to 15-20% more errors than before.

Hospitals must reduce the workload of training physicians, not just the hours.