RT Journal Article SR Electronic T1 National improvements in resident physician-reported patient safety after limiting first-year resident physicians’ extended duration work shifts: a pooled analysis of prospective cohort studies JF BMJ Quality & Safety JO BMJ Qual Saf FD BMJ Publishing Group Ltd SP 81 OP 89 DO 10.1136/bmjqs-2021-014375 VO 32 IS 2 A1 Weaver, Matthew D A1 Landrigan, Christopher P A1 Sullivan, Jason P A1 O'Brien, Conor S A1 Qadri, Salim A1 Viyaran, Natalie A1 Czeisler, Charles A A1 Barger, Laura K YR 2023 UL http://qualitysafety.bmj.com/content/32/2/81.abstract AB Background The Accreditation Council for Graduate Medical Education (ACGME) enacted a policy in 2011 that restricted first-year resident physicians in the USA to work no more than 16 consecutive hours. This was rescinded in 2017.Methods We conducted a nationwide prospective cohort study of resident physicians for 5 academic years (2002–2007) before and for 3 academic years (2014–2017) after implementation of the 16 hours 2011 ACGME work-hour limit. Our analyses compare trends in resident physician-reported medical errors between the two cohorts to evaluate the impact of this policy change.Results 14 796 residents provided data describing 78 101 months of direct patient care. After adjustment for potential confounders, the work-hour policy was associated with a 32% reduced risk of resident physician-reported significant medical errors (rate ratio (RR) 0.68; 95% CI 0.64 to 0.72), a 34% reduced risk of reported preventable adverse events (RR 0.66; 95% CI 0.59 to 0.74) and a 63% reduced risk of reported medical errors resulting in patient death (RR 0.37; 95% CI 0.28 to 0.49).Conclusions These findings have broad relevance for those who work in and receive care from academic hospitals in the USA. The decision to lift this work hour policy in 2017 may expose patients to preventable harm.Data are available on reasonable request.