Methods & Sources

Every number on Nevvi is public CMS data, presented as-is. Here is exactly where it comes from and what it does — and doesn't — mean.

The sources

• CMS Medicare Physician & Other Practitioners Public Use File (Part B). The core of the product: service counts and provider-submitted charges by provider and by CPT/HCPCS code, published annually by CMS. This is where volumes and charges come from.
• CMS Doctors & Clinicians files. Group membership, practice locations, and hospital affiliations — used to roll individual providers up into physician groups and to flag independent vs. hospital-affiliated practices. Archived yearly snapshots back the trend view.
• CMS Medicare Monthly Enrollment. Fee-for-service beneficiary counts by state, used as the denominator for per-capita context.
• CDC PLACES and BRFSS (disease-burden context). Used only in the trend reports to add population health context alongside utilization — not in the free lookup. These are modeled, all-payer, adult-population estimates and carry their own denominator caveat, stated in each report.

Coverage

The most recent CMS annual release (CY2024) spans all 50 states plus territories, 5,410 CPT/HCPCS codes, 76,617 physician groups, and 1,207,473 providers. The trend layer covers twelve consecutive calendar years (CY2013–CY2024).

What the numbers mean — and their limits

Reading Medicare data well means knowing its edges. These apply everywhere on the site:

• Medicare fee-for-service only — not all-payer. Figures reflect Original Medicare. They do not include Medicare Advantage, commercial insurance, Medicaid, or cash-pay volume, so they are a consistent proxy for a practice's activity, not its total book of business.
• Small counts are suppressed. CMS withholds any provider×code figure based on fewer than 11 beneficiaries before publication. A missing row means "suppressed," never zero — so totals for low-volume codes understate reality.
• "Charges" are submitted amounts, not payments. They're what the provider billed, not what Medicare allowed or paid. Useful for relative comparison across providers; not a revenue figure.
• Each year is CMS's most recent annual release. Calendar-year data reflects the vintage CMS has published; there is a natural lag between a service year and its release.

How plain-English search works

When you type a question instead of a code, the question text is sent to the Claude API to translate it into the matching CPT/HCPCS codes — that translation is the only thing the AI does. Every count, charge, and ranking you then see is queried directly from our database of CMS data. No figure on Nevvi is generated, estimated, or inferred by an AI model.

Rankings

Groups are ordered by measured Medicare fee-for-service service volume for the code and geography you searched — a direct read of the CMS data, not a rating or a score. Nevvi does not grade providers or judge quality of care; it reports what the public record shows.

Updates

Nevvi refreshes when CMS publishes — annually for the Part B file, on each source's own cadence for the affiliation and enrollment files. The data footer on every page names the source vintage and load date currently in service.

Citing Nevvi

Please attribute as: "Nevvi (nevvi.app), from the CMS Medicare Physician & Other Practitioners PUF." Nevvi is a product of TinyFlux Studio and is not affiliated with CMS or HHS.

Questions

Spot something that looks wrong, or want more detail on a method? Contact us or email [email protected] — corrections are welcome.