Physician

Key facts

Degrees

MD (allopathic) or DO (osteopathic)

Licensing

State medical boards; some states have separate MD and DO boards

Licensing exams

USMLE (MD and DO graduates) or COMLEX-USA (DO graduates)

Postgraduate training

ACGME-accredited residency, typically 3 to 7 years

Medicare definition

Section 1861(r) of the Social Security Act

What is a physician?

Physicians complete a four-year medical degree followed by graduate medical education (GME) in a residency program, and often a fellowship in a subspecialty. MD and DO physicians have the same practice rights in every state. DO training adds osteopathic manipulative treatment, but both groups work across all specialties.

A state license is the legal permission to practice. Board certification in a specialty is a separate, voluntary credential, although many hospitals and health plans require it. Graduates of medical schools outside the United States must also obtain certification from the Educational Commission for Foreign Medical Graduates (ECFMG) before entering U.S. residency.

How physicians are classified

Provider data usually describes physicians along several dimensions:

• Degree: MD or DO.
• Specialty: primary care fields such as family medicine, internal medicine and pediatrics, or specialties such as cardiology, oncology and orthopedic surgery.
• Practice setting: independent practice, health system employment, academic medical centers, government service or industry.
• Training status: residents and fellows still in training versus fully trained attending physicians.

Who counts as a physician in Medicare

Medicare uses a wider definition. Section 1861(r) of the Social Security Act includes doctors of medicine and osteopathy and, for services within their scope, dentists, podiatrists, optometrists and chiropractors, with chiropractors limited to manual manipulation of the spine to correct a subluxation.

Datasets built on Medicare rules can therefore label a podiatrist or optometrist as a physician, while taxonomy-based data places those professions in separate groupings.

Why physician data matters

Physicians prescribe, order tests and procedures, direct hospital admissions and anchor referral networks. Their NPIs connect NPPES records, Medicare enrollment, Part B and Part D utilization, Open Payments and hospital affiliations, which makes the physician the core unit for pharma targeting, network analysis, recruitment and market sizing. Residents and fellows also hold NPIs, so analyses of practicing physicians usually separate trainees from fully trained clinicians.