You may know that the 2021 U.S. News & World Report’s Best Hospitals list ranked Keck Medical Center of USC among the top 50 in the country in 12 specialties, but how are those rankings achieved? And how does physician voting play a role?

The Best Hospitals rankings identify medical centers nationwide that are best able to care for patients with unusual or difficult diagnoses in 15 specialties. A vital component of those scores comes from “expert opinion” — physicians voting for hospitals they consider the best for patients in their specialty. This voting occurs via an online survey of physicians registered on Doximity, an online networking service for medical professionals.

According to U.S. News’ hospital rankings 2021-2022 methodology report, three of the specialty rankings (ophthalmology, psychiatry and rheumatology) rely solely on expert opinion. Twelve of the specialty rankings are based on data-driven analysis of performance in the following categories: the institution’s structure, expert opinion, patient experience and outcomes.

The structural measures include hospital volume, nurse staffing and other resources. Outcomes performance relies on patient survival and the rate at which hospitals discharge patients to home following inpatient care.

Expert opinion accounts for 27.5% of the overall U.S. News ranking for most of the specialties, and it is the part of the score that physicians can impact by voting.

A hospital’s expert opinion score is based on the average number of nominations from the three most recent annual surveys of board-certified physicians conducted. The surveyed physicians are asked to nominate the hospitals in their specific field, without consideration of expense or location, that they consider best for patients with serious or difficult conditions. They can list as many as five hospitals.

Board-certified physicians in the 15 adult ranked specialty areas who are registered as Doximity users are eligible to complete an online survey during the online voting period, which opened last week and is expected to end sometime in March. More detailed information about eligibility requirements for voting physicians can be found at

The current 15 specialty rankings are: cancer, cardiology and heart surgery; diabetes & endocrinology; ear, nose & throat; gastroenterology & GI surgery; geriatrics; gynecology; neurology & neurosurgery; ophthalmology; orthopedics; pulmonology & lung surgery; psychiatry; rehabilitation; rheumatology; and urology.