# Method

Source: CMS Doctors and Clinicians National Downloadable File, fetched 2026-09-15.
3,388,628 rows, 1,627,468 distinct NPIs.

- One clinician per NPI. The Telehlth field is the same on every row of an NPI except one.
- Doctors: credential field MD or DO (703,381 NPIs). 322,737 clinicians have a blank credential and are left out of the doctor counts, so some doctors are missing.
- Specialty is the primary specialty (pri_spec).
- Virtual practice address: address line 1 or 2 contains virtual, telehealth, telemed, tele-health or online.
- The file covers clinicians enrolled in Medicare. Doctors who do not bill Medicare are not in it.