How we source, compute, and verify everything on this site
Every number on this site is computed from public CMS data using the published Medicare payment rules, versioned so it can be reproduced later, and cited back to the exact file it came from. This page explains how.
Where the data comes from
All rate data is ingested from the files CMS publishes for each quarterly Physician Fee Schedule release: the PPRRVU file (RVUs, status indicators, policy indicators, and the conversion factor), the GPCI file (the three geographic indexes per payment locality), the ZIP-code-to-locality crosswalk, per-locality anesthesia conversion factors, OPPS site-of-service caps, and the NCCI edit files. We archive the raw source files as received, so every ingested value can be traced to the row it came from.
How rates are computed
Rates are computed with Medicare's published formula — (work RVU × work GPCI + practice expense RVU × PE GPCI + malpractice RVU × MP GPCI) × conversion factor — using the facility or non-facility practice expense value for the requested setting. Whether a code pays at all is decided by its status indicator, never by whether RVU values happen to be present: a blank RVU is treated as missing, not as zero, and carrier-priced codes are reported as having no national amount rather than a made-up figure. Sequestration is applied only as an optional, final step — never baked into the underlying rate. The full walkthrough is in How Medicare pays.
Versioning: releases are immutable
Each quarterly release (year plus A/B/C/D quarter) is ingested as its own immutable dataset — a published release is never edited in place. When CMS revises a file, we ingest the revision as a new version alongside the old one. That is what makes historical lookups trustworthy: a rate retrieved for Q2 2024 always answers with Q2 2024 data, and every page and API response states which release produced its numbers.
Parsing without guessing
CMS shifts column order, header names, and title rows between releases, so our ingest locates the header row and maps columns by name against a maintained alias table — never by fixed position. If a required column can't be found, the ingest fails loudly instead of guessing. Wrong-but-plausible data is worse than no data.
How the explanatory content is written and verified
The glossary and guides are original prose written from primary CMS sources, each page listing the sources it draws on with followed links. Specific factual claims are tracked individually: each claim is tied to its source, re-verified against the source's actual text, and its verification resets automatically whenever either the claim or the source URL changes. Source links are checked for rot on a schedule. Reference pages show the date their content last materially changed — real revision dates, never decorative ones.
What we deliberately don't show
Official CPT code descriptions are copyrighted by the American Medical Association, so public pages carry our own original descriptions written from primary sources rather than AMA descriptor text. HCPCS Level II descriptions are maintained by CMS and shown freely. And where an answer genuinely requires more information — a ZIP that spans two localities, a carrier-priced code, a blank RVU — we say so instead of inventing a number.
Corrections
If you find a number or a claim you believe is wrong, we want to know: micah@linkfount.com. Corrections to explanatory content update the page's revision date; corrections to rate data arrive as new release revisions, preserving what was previously published.