The 2003 regulations that limited resident duty hours substantially altered graduate medical education. Although the reductions were implemented with the stated goal of improving patient safety, clinical outcomes remain largely unchanged. A potential unintended consequence of decreased duty-hours is decline in educational quality leading to lack of preparedness for independent practice. To examine physician performance after training, this study compared senior physicians (with 10 or more years of post-residency experience) to new physicians (with no more than 1 year of experience) who had reduced duty-hours during training. The authors found no difference in terms of their patients' length of stay or hospital mortality. These results show that the 2003 regulations did not worsen patient outcomes, but they do not address the more sweeping 2011 duty hours reforms prompted by the 2008 Institute of Medicine work hours report.