ABSTRACT: Several prior studies have examined the impact of learners (medical students or residents) on overall emergency department (ED) flow as well as the impact of resident training level on the number of patients seen by residents per hour. No study to date has specifically examined the impact of learners on emergency medicine (EM) attending physician productivity, with regards to patients per hour (PPH). We sought to evaluate whether learners increase, decrease, or have no effect on the productivity of EM attending physicians in a teaching program with one student or resident per attending.This was a retrospective database review of an urban, academic tertiary care center with 3 separate teams on the acute care side of the ED. Each team was staffed with one attending physician paired with either one resident, one medical student or with no learners. All shifts from July 1, 2008 to June 30, 2010 were reviewed using an electronic database. We predefined a shift as "Resident" if > 5 patients were seen by a resident, "Medical Student" if any patients were seen by a medical student, and "No Learners" if no patients were seen by a medical student or resident. Shifts were removed from analysis if more than one learner saw patients during the shift. We further stratified resident shifts by EM training level or off-service rotator. For each type of shift, the total number of patients seen by the attending physician was then divided by 8 hours (shift duration) to arrive at number of patients per hour.We analyzed a total of 7,360 shifts with 2,778 removed due to multiple learners on a team. For the 2,199 shifts with attending physicians with no learners, the average number of PPH was 1.87(95% confidence interval [CI] 1.86,1.89). For the 514 medical student shifts, the average PPH was 1.87(95% CI 1.84,1.90), p = 0.99 compared with attending with no learner. For the 1,935 resident shifts, the average PPH was 1.99(95% CI 1.97,2.00). Compared with attending physician with no learner, attending physicians with a resident saw more PPH (1.99 vs 1.87, p<0.005). There was no statistically significant difference found between EM1: 1.98PPH, EM2: 1.99PPH, EM3: 1.99PPH, and off-service rotators: 1.99PPH.EM attending physicians paired with a resident in a one-on-one teaching model saw statistically significantly more patients per hour (0.12 more patients per hour) than EM attending physicians alone. EM attending physicians paired with a medical student saw the same number of patients per hour compared with working alone.