Milestone achievements in a national sample of pediatric emergency medicine fellows: impact of primary residency training.

Background: Pediatric emergency medicine (PEM) fellowships recruit trainees from both pediatric and emergency medicine (EM) residencies. The Accreditation Council for Graduate Medical Education (ACGME) defines separate training pathways for each. The 2015 PEM milestones reflect a combination of subcompetencies from the two residencies.