Application in Parallel to U.S. Residency Training Programs in Multiple Specialties: Trends and Differences by Applicant Educational Background, 2009-2021.

All applicant groups experienced decreases in percentages parallel applying except for DO applicants. Parallel application appears to be common and slowly declining, and does not appear to significantly contribute to increasing numbers of applications per candidate. Efforts to control the growth of applications per applicant should continue to focus on applicants' numbers of applications submitted to each specialty.