Although the 2003 duty hour regulations for resident physicians were intended as a patient safety intervention, concerns were raised that the rules might actually result in patient harm by increasing handoffs. These concerns were allayed by prior studies that found no increase in mortality at teaching hospitals after duty hours were restricted. This follow-up study tracked 5-year outcomes among Medicare patients and found no increase in mortality rates at teaching hospitals compared with less teaching-intensive hospitals. While it now appears clear that the 2003 duty hour limits had little impact on either safety outcomes or clinical outcomes, the effect of further regulations implemented in 2011 remains to be seen.