What this methodology is
This page is the public, versioned methodology for the Gastroenterology Provider Supply by State dataset. It documents how the figures defined by the matched Fonteum Research study, /api/v1 endpoint, and Audit Pack were constructed — from registered public-source ingest through aggregation rules to the rendered output. It exists so buyers can satisfy auditor questions by linking to a single durable URL.
The sections below define Fonteum's transformation rules. Where the methodology differs from the underlying source's own description (for example: which taxonomies count, how Type-1 vs Type-2 NPIs are treated, how density per 100k is computed), the rule lives here, not in the source. Methodology versions (v2026.05.0 today) increment when those rules change; recorded snapshot observations are listed separately from publisher cadence and appear only where this manifest includes them.
Source provenance
- Source families
- CMS NPPES NPI Registry (public API) + U.S. Census Bureau Population Estimates Program (PEP) V2025
- Spatial resolution
- State (50 + DC). NPPES does not publish a county-level field of practice in its public API.
- Temporal coverage
- 2026 snapshot (NPPES queried 2026-05-06; Census 2024 vintage).
- Publisher cadence
- Quarterly NPPES refresh; annual Census denominator update.
- Snapshot scope
- 21,236 gastroenterologists across 51 states + DC; snapshot dated May 6, 2026.
The Fonteum sources registry holds the canonical entry for each source family — Tier classification, ToS posture, publisher cadence, and catalog status. Publisher cadence is not a loaded-date guarantee: /sources.
Reproducibility statement
An independent researcher with access only to the public sources listed above can recreate this dataset by following these steps. Discrepancies between an independent reproduction and the published figures belong in /corrections-log; we publish them when they arise.
Limitations
Limitations are surfaced explicitly, not buried. Each item below is a constraint a buyer’s compliance team should review before relying on the dataset for a specific use case.
- Counts NPI-1 individual providers only; the parent specialty taxonomy plus any subspecialty taxonomies the §183 / §188 ingest scoped to. PAs / NPs / CNMs working in the same care setting under different taxonomy codes are out of scope.
- Dataset measures density (per-capita supply), not access. Drive time, appointment availability, insurance acceptance, and wait times are not modeled.
- Underserved threshold is the parent study's transparent baseline cutoff, not a regulatory or clinical definition.
- Provider state is the practice-address state in NPPES. NPPES does not publish a county-level field of practice in its public API; county queries surface state-level density.
- NPPES last_updated reflects when CMS last touched the record — providers may have moved, retired, or changed practice settings without updating their NPPES record. Roughly 5-15% of records have last_updated > 5 years per CMS published quality reports.
- U.S. Census Bureau PEP V2025 (2024 vintage) state population. Annual estimates between decennial counts; Census itself documents a confidence band of ~0.5-2% depending on state.
- Estimates do not reflect mid-2025+ population movements. Major hurricane / wildfire displacements may distort per-capita ratios for several quarters until next vintage.
Field schema
This manifest lists the documented fields for this dataset with source, publisher-cadence, and confidence definitions. Runtime responses can return a subset, and record-level provenance fields may be null or absent.
| Field | Description | Source | Publisher cadence | Confidence |
|---|---|---|---|---|
npi | Individual provider NPI (10-digit). | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
taxonomy_codes | All NUCC taxonomy codes attached to the record (primary + subspecialties). | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
taxonomy_primary | The provider's primary NUCC taxonomy code. | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
state | Practice-address state (USPS code) at the time of NPPES record's last_updated. | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
city | Practice-address city at the time of NPPES record's last_updated. | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
last_updated | When CMS last modified the NPPES record. Reflects record freshness, not Fonteum snapshot date. | CMS NPPES NPI Registry (public API) ↗ | Quarterly | 1.0 (verbatim) |
population_2024 | PEP V2025 state population estimate for 2024 vintage. | U.S. Census Bureau Population Estimates Program (PEP) V2025 ↗ | Annual (V<year> vintage releases each March) | 1.0 (verbatim) |
count | gastroenterologists active in NPPES as of snapshot date. The §193 sub-specialty filter parameter (`?subspecialty=<NUCC code>`) on the public API recomputes counts and density against any registered subspecialty taxonomy. | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.95 |
per_100k | gastroenterologists per 100,000 residents (count ÷ population × 100,000). | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.95 |
rank_density | 1..51 rank by per_100k across U.S. states + DC. | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.95 |
rank_count | 1..51 rank by absolute count. | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.95 |
quartile | Q1..Q4 from rank_density. | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.95 |
underserved | Boolean: per_100k below the transparent threshold defined in the parent study. | Fonteum Research (derived from CMS NPPES + U.S. Census Bureau) | Recomputed on each NPPES + Census refresh cycle | 0.90 |
Version history
The methodology versions recorded in this manifest appear here with their change rationale. A listed data-only snapshot observation can appear as a same-version entry; the table is not a universal history or replay service.
| Version | Released | What changed |
|---|---|---|
v2026.05.0current | May 6, 2026 | Initial Audit Pack release. Methodology, provenance map, reproducibility statement, and limitations stack baselined. |
Cite this methodology
For procurement attachments, audit responses, footer attribution, or academic use. Pick a format and copy.
Downloads & cross-references
- Research study → the editorial findings + charts
- JSON methodology metadata — for programmatic ingestion
- Download per-state CSV
- Download per-state JSON
Methodology questions: methodology@fonteum.com. Data corrections: /corrections-log. B2B inquiries: api@fonteum.com.
This page is the durable URL a buyer’s compliance officer can link from their product. The version pinned at the URL (v2026.05.0) is the active methodology. The Version history table is a changelog, not a promise that each historical dataset snapshot remains queryable.