The 2003 regulations reducing housestaff duty hours have been controversial. Although some research has shown fewer errors when housestaff worked shorter shifts, many commentators have raised concern about the potential for errors associated with more transfers of care between physicians. This study sought to directly examine the effect of duty hours limitations on clinical outcomes by comparing medical patients hospitalized on a resident service to patients on a non-teaching service before and after duty hour reduction. There was no detectable increase in adverse events among patients cared for by residents, and some outcomes improved (eg, potential medication errors). Another study in the same issue also found reduced inpatient mortality among medical (but not surgical) patients after implementation of duty hour limitations. The accompanying editorial discusses these two studies in the context of growing evidence that limiting work hours "does no harm" to patients.