OBJECTIVE: Differences in the quality of emergency department (ED) care are often attributed to nonclinical factors such as variations in the structure, systems, and processes of care. Few studies have examined these associations among children. We aimed to determine whether process measures of quality of care delivered to patients receiving care in children's hospital EDs were associated with physician-level or hospital-level factors. METHODS: We included children (<18 years old) who presented to any of the 12 EDs participating in the Pediatric Emergency Care Applied Research Network (PECARN) between January 2011 and December 2011. We measured quality of care from medical record reviews using a previously validated implicit review instrument with a summary score ranging from 5 to 35, and examined associations between process measures of quality and physician- and hospital-level factors using a mixed-effects linear regression model adjusted for patient case-mix, with hospital site as a random effect. RESULTS: Among the 620 ED encounters reviewed, we did not find process measures of quality to be associated with any physician-level factors such as physician sex, years since medical school graduation, or physician training. We found, however, that process measures of quality were positively associated with delivery at freestanding children's hospitals (1.96 points higher in quality compared to nonfreestanding status, 95% confidence interval: 0.49, 3.43) and negatively associated with higher annual ED patient volume (-0.03 points per thousand patients, 95% confidence interval: -0.05, -0.01). CONCLUSION: Process measures of quality of care delivered to children were higher among patients treated at freestanding children's hospitals but lower among patients treated at higher volume EDs.