National Dermatology Supply by State — NPPES 2026 Snapshot
Active U.S. dermatologists per 100,000 residents, by state, from the public CMS NPI Registry.
Contents · 13 sections
- Why a public-records dermatology supply view matters
- What we counted, and what we did not
- Headline: density spread is larger than the national figure suggests
- Underserved jurisdictions under the 4-per-100k threshold
- Density vs. spatial access: what this study cannot say
- Public-health frame
- Why this is different: public-records-only, record-level traceable
- Cite this study
- Limitations
- Limitations
- Methodology
- Technical appendix
- Cite this study
Executive Summary
- All counts in this study describe active NPI-1 (individual practitioner) Dermatology providers in the public CMS NPI Registry (NPPES) as of the 2026-05-06 snapshot. Practice Address state is used; Mailing Address is not. 18,765 providers across 51 states + DC.
- National density is 5.52 active dermatologists per 100,000 residents (Census 2024 vintage population). District of Columbia leads at 11.68 / 100k (n=82). The top 3 by density are District of Columbia, Massachusetts, and Rhode Island.
- Arkansas, West Virginia, Wyoming, Mississippi, and Nevada per 100k anchor the bottom of the ranking. Arkansas ranks last at 3.11 / 100k (n=96).
- 16 jurisdictions fall below the stated 4-per-100,000 underserved threshold defined in this study's methodology — collectively 55,739,099 residents. The threshold is a transparent baseline cutoff, not a clinical or regulatory definition.
- This is provider density, not spatial access. A per-100k figure does not measure new-patient availability, insurance acceptance, sub-specialty match, or travel time to the nearest practice. Network-based / E2SFCA / gravity methods give a more accurate picture of geographic access; we cite the relevant 2023–2025 spatial-access literature in the methodology.
At a glance — for journalists, researchers, and AI agents
What this dataset covers
- U.S.-state-level density of active NPI-1 Dermatology providers per 100,000 residents, computed from the public CMS NPI Registry (NPPES) and the U.S. Census Bureau 2024 Vintage state population estimates.
- Full ranking of 50 states + DC by density, with quartile bands and an explicit 4-per-100k underserved threshold defined in the study's methodology.
- Density-versus-spatial-access framing, citing the relevant 2023–2025 spatial-access literature for follow-up reading.
What this dataset does NOT cover
- Clinical access modeling (E2SFCA, gravity, drive-time isochrones) — explicitly out of scope.
- Board-certification status, sub-specialty expertise, insurance acceptance, new-patient availability, or any clinical-outcomes metric for any individual provider.
- Type 2 (organization / group practice) NPIs and adjacent-discipline providers (e.g. NPs, PAs, psychologists for psychiatry) — separate analysis surfaces.
Sources
- CMS NPPES
- U.S. Census Bureau
Snapshot date: 2026-05-06 NPPES snapshot
Dataset scope · Snapshot May 6, 2026
Includes: active business listings indexed in the Ownlisted directory network, sourced from public Google Business Profiles. Does not include: online-only operators without a physical service address, lead-generation shells, or businesses with no public review footprint. Counts describe the Ownlisted indexed provider dataset — not a representative sample of the U.S. local-services market.
Key findings
Why a public-records dermatology supply view matters
Dermatology access has been a public-health concern for two decades. A 2025 network-based cross-sectional study (Glezer et al., Journal of the American Academy of Dermatology / JAMA-style submission) reported that 96.6% of U.S. residents live within one hour of at least one dermatologist — but more than 11 million Americans remain in regions classified as underserved under that paper's network-distance methodology. The national headline ("most Americans have access") and the state-level reality ("a sixth of states are underserved by any reasonable density threshold") tell different stories.
This study reports what the public NPPES dataset shows. It is a density measurement at state granularity. It is not a spatial-access model. Where access modeling is appropriate — and where it changes the answer materially — the methodology section cites the relevant literature and points readers there.
What we counted, and what we did not
Source. The U.S. Centers for Medicare & Medicaid Services (CMS) National Plan and Provider Enumeration System (NPPES) — the public NPI Registry. Every U.S. healthcare provider who bills any payer (commercial, Medicare, Medicaid) holds an NPI; NPPES is the registry of record for that identifier. The public API at https://npiregistry.cms.hhs.gov/api/?version=2.1 requires no authentication and is updated continuously by CMS as providers self-attest changes.
Counted (kept). Each provider in our snapshot meets all three criteria:
Type 1 NPI (individual practitioner). Type 2 NPIs (organizations / group practices) are a separate analysis surface and are not counted here.
Active —
basic.status = "A"andbasic.deactivation_dateis null.At least one Healthcare Provider Taxonomy code in the dermatology family:
207N00000X— Dermatology (parent)207ND0900X— Dermatopathology207NI0002X— Clinical & Laboratory Dermatological Immunology207NP0225X— Pediatric Dermatology207NS0135X— Procedural Dermatology / MOHS
A single provider may carry multiple taxonomies (e.g., a MOHS-trained dermatopathologist holding the parent code plus 207ND0900X and 207NS0135X). Each provider is counted once at their Practice Address state. Physician assistants in dermatology offices carry their own taxonomy (363AS0400X) and are excluded.
State assignment. Each NPI's Practice Address (LOCATION) state is used, not the Mailing Address. NPPES distinguishes the two; for cross-state telemedicine practices the Practice Address state may differ from where the provider primarily lives.
Not counted. Providers with deactivated NPIs, providers whose only dermatology-adjacent taxonomy is outside the codes above, residents and fellows whose primary taxonomy is the "Student" code (390200000X), and providers without a U.S. Practice Address.
Headline: density spread is larger than the national figure suggests
The national rate of 5.52 active dermatologists per 100,000 residents is a single number; the state spread is what consumers, providers, and policy readers actually feel.
Top 5 by density:
- District of Columbia — 11.68 / 100k (n=82)
- Massachusetts — 9.84 / 100k (n=702)
- Rhode Island — 8.09 / 100k (n=90)
- Connecticut — 7.92 / 100k (n=291)
- New York — 7.27 / 100k (n=1,444)
Bottom 5 by density:
- Arkansas — 3.11 / 100k (n=96)
- West Virginia — 3.16 / 100k (n=56)
- Wyoming — 3.23 / 100k (n=19)
- Mississippi — 3.30 / 100k (n=97)
- Nevada — 3.34 / 100k (n=109)
The lowest-density state holds approximately 27% of the highest-density jurisdiction's per-capita supply. The chart below shows the full ranking; the dashed marker is the 4-per-100k threshold this study uses to flag underserved jurisdictions.
U.S. dermatologists per 100,000 residents — full state ranking
Sorted by per-capita density (highest first). Active NPI-1 Dermatology providers from NPPES snapshot 2026-05-06 against U.S. Census 2024 vintage state population. Quartile column: 1 = top quartile (highest density); 4 = bottom quartile. Underserved column flags jurisdictions below the 4-per-100k threshold defined in the methodology.
| State | State name | Active dermatologists | Per 100k | Density rank | Quartile | <4/100k? |
|---|---|---|---|---|---|---|
| DC | District of Columbia | 82 | 11.68Highest | 1 | 1 | — |
| MA | Massachusetts | 702 | 9.84 | 2 | 1 | — |
| RI | Rhode Island | 90 | 8.09 | 3 | 1 | — |
| CT | Connecticut | 291 | 7.92 | 4 | 1 | — |
| NY | New York | 1,444 | 7.27 | 5 | 1 | — |
| NH | New Hampshire | 102 | 7.24 | 6 | 1 | — |
| MN | Minnesota | 377 | 6.51 | 7 | 1 | — |
| SD | South Dakota | 60 | 6.49 | 8 | 1 | — |
| FL | Florida | 1,500 | 6.42 | 9 | 1 | — |
| CA | California | 2,508Highest | 6.36 | 10 | 1 | — |
| MD | Maryland | 394 | 6.29 | 11 | 1 | — |
| CO | Colorado | 371 | 6.23 | 12 | 1 | — |
| PA | Pennsylvania | 807 | 6.17 | 13 | 1 | — |
| UT | Utah | 214 | 6.11 | 14 | 2 | — |
| WI | Wisconsin | 362 | 6.07 | 15 | 2 | — |
| IL | Illinois | 731 | 5.75 | 16 | 2 | — |
| HI | Hawaii | 83 | 5.74 | 17 | 2 | — |
| OR | Oregon | 242 | 5.66 | 18 | 2 | — |
| AZ | Arizona | 426 | 5.62 | 19 | 2 | — |
| VA | Virginia | 493 | 5.60 | 20 | 2 | — |
| WA | Washington | 445 | 5.59 | 21 | 2 | — |
| MI | Michigan | 556 | 5.48 | 22 | 2 | — |
| MT | Montana | 62 | 5.45 | 23 | 2 | — |
| NC | North Carolina | 585 | 5.30 | 24 | 2 | — |
| NJ | New Jersey | 490 | 5.16 | 25 | 2 | — |
| MO | Missouri | 322 | 5.16 | 26 | 2 | — |
| OH | Ohio | 608 | 5.12 | 27 | 3 | — |
| VT | Vermont | 33 | 5.09 | 28 | 3 | — |
| LA | Louisiana | 233 | 5.07 | 29 | 3 | — |
| ND | North Dakota | 38 | 4.77 | 30 | 3 | — |
| SC | South Carolina | 256 | 4.67 | 31 | 3 | — |
| NE | Nebraska | 88 | 4.39 | 32 | 3 | — |
| TX | Texas | 1,358 | 4.34 | 33 | 3 | — |
| TN | Tennessee | 311 | 4.30 | 34 | 3 | — |
| ME | Maine | 58 | 4.13 | 35 | 3 | — |
| AL | Alabama | 202 | 3.92 | 36 | 3 | yes |
| KS | Kansas | 115 | 3.87 | 37 | 3 | yes |
| GA | Georgia | 431 | 3.85 | 38 | 3 | yes |
| IN | Indiana | 266 | 3.84 | 39 | 3 | yes |
| IA | Iowa | 124 | 3.83 | 40 | 4 | yes |
| KY | Kentucky | 175 | 3.81 | 41 | 4 | yes |
| OK | Oklahoma | 148 | 3.61 | 42 | 4 | yes |
| DE | Delaware | 37 | 3.52 | 43 | 4 | yes |
| AK | Alaska | 26 | 3.51 | 44 | 4 | yes |
| ID | Idaho | 69 | 3.45 | 45 | 4 | yes |
| NM | New Mexico | 73 | 3.43 | 46 | 4 | yes |
| NV | Nevada | 109 | 3.34 | 47 | 4 | yes |
| MS | Mississippi | 97 | 3.30 | 48 | 4 | yes |
| WY | Wyoming | 19 | 3.23 | 49 | 4 | yes |
| WV | West Virginia | 56 | 3.16 | 50 | 4 | yes |
| AR | Arkansas | 96 | 3.11 | 51 | 4 | yes |
Underserved jurisdictions under the 4-per-100k threshold
16 jurisdictions rank below the 4 active dermatologists per 100,000 residents threshold this study uses to flag underserved jurisdictions. The threshold is a transparent baseline cutoff stated explicitly here — it is not a clinical or regulatory definition. Transparent baseline cutoff that sits roughly at the lower bound of access-gap thresholds reported in the 2023 spatial-access literature and the AAMC dermatology workforce reports. Stated explicitly here; not a clinical or regulatory definition.
The states below the threshold collectively hold 55,739,099 residents — about 16.4% of the U.S. population.
Important framing. "Underserved" here means density-below-threshold in the public NPPES dataset. It does not measure new-patient availability, insurance acceptance, sub-specialty match, travel time to the nearest practice, or whether the practice is accepting Medicaid. Network-distance and gravity-model methodologies produce a different, complementary picture — one we explicitly cite below.
Density vs. spatial access: what this study cannot say
Density per 100,000 residents is the most transparent supply baseline. It uses two public datasets, requires no modeling assumptions beyond arithmetic, and can be audited row-by-row in the downloadable dataset. Every reader can audit the numbers themselves.
It is not spatial access. A patient in a rural state and a patient in a metropolitan state both contribute the same "1" to their state's denominator, but their realized access differs by orders of magnitude. Headline figures derived from network-distance models (e.g. "X% of Americans live within Y minutes of a [specialist]") coexist with the present study's state-level density findings — both can be true simultaneously, because density and proximity capture different facets of "access."
The healthcare workforce literature has more advanced approaches:
- Two-Step Floating Catchment Area (E2SFCA) and gravity models treat access as a function of provider supply, population demand, and distance decay. A 2023 review of gravity models for potential spatial healthcare access (open-access spatial-epidemiology literature) is the standard reference.
- Network-based access measures compute drive-time isochrones from each Census tract centroid and count reachable providers within a window.
This study does not implement E2SFCA, gravity, or network distance. It reports state-level density and acknowledges the gap. Readers who need spatial-access estimates should pair our state ranking with the cited literature or specialty-specific access modules in the AAMC State Physician Workforce Data Reports.
Public-health frame
A 2023 paper on dermatologist demographic density and melanoma outcomes (peer-reviewed dermatology-policy literature) found that lower density was associated with worse melanoma outcomes, with the largest gains observed when areas moved from zero to modest dermatologist presence rather than from already-saturated to even more saturated. The shape of the relationship matters: doubling provider supply in a top-decile state buys little; adding the first practice to a county that has none can change outcomes materially.
The bottom-quartile states in this study — particularly Arkansas, West Virginia, Wyoming, Mississippi — are the supply-side cohort where the public-health literature suggests adding capacity has the highest marginal value. We are not claiming a causal link between any specific state's NPPES count and any specific outcome metric; the cited paper makes that argument with the appropriate covariate adjustment, and we link to it for readers who want the full chain.
A separate Medscape 2026 commentary, A Potential Solution to Access Issues in Rural America, flags telemedicine and PA-led dermatology clinics as the principal capacity-expansion pathways. Both expand access without changing the NPI-1-dermatologist count this study tracks — the 2026 NPPES snapshot does not yet reflect that capacity. Future updates of this study will distinguish dermatologist-NPI-1 supply from PA-augmented-clinic supply once a public dataset surfaces.
Citation transparency. This study makes no clinical claims about any individual provider. The melanoma-outcomes link is one published in the literature; we cite it as context for why density matters, not as a finding our dataset proves.
Why this is different: public-records-only, record-level traceable
Most state-level dermatology supply numbers in circulation come from one of three places: (1) the AAMC State Physician Workforce reports, which use specialty-society membership and AMA Masterfile cross-references; (2) commercial workforce-data vendors that license those underlying datasets; or (3) press-release figures from advocacy organizations.
This study is different in three concrete ways:
- Single public source family. Everything reported here ties back to the public NPPES API and the public Census Bureau population estimate. Both are free. Both are updated on cadences CMS and Census publish. Anyone with a web browser can re-run the underlying queries.
- Record-level traceability. Every provider in the count has an NPI. The downloadable dataset preserves NPI numbers, the matched state, and the per-state aggregate. A reader auditing a specific state's count can pull the corresponding NPI list, look each one up in NPPES, and audit the active-dermatology-taxonomy criterion themselves.
- No quality attestation. Fonteum does not run a checking process for individual dermatologists. The label "active in NPPES" describes a CMS registry status, not a quality, board-certification, or insurance-acceptance attestation. Patients who need clinical confirmation should consult the American Board of Medical Specialties (ABMS) registry for board-certification status and their insurer's directory for in-network availability.
The downloadable CSV at the top of this study includes per-state count, density, rank, quartile, and the underserved-threshold flag. The downloadable JSON adds the snapshot metadata and source URLs.
Cite this study
Suggested citation:
Ownlisted Research. (2026). National Dermatology Supply by State — NPPES 2026 Snapshot. Ownlisted. Retrieved from https://fonteum.com/research/dermatology-provider-supply-by-state-2026
Reuse and attribution. Charts, tables, and the downloadable CSV / JSON may be cited or reproduced with attribution to Ownlisted Research and a link to this study. Carry the snapshot date (2026-05-06) so readers know the dataset version. Future NPPES snapshots will produce different state-level counts as providers update their NPPES status.
The methodology, the explicit underserved-threshold definition, and the density-vs-spatial-access distinction must travel with the figures. Per-state counts published without those caveats risk being misread as a clinical-access measurement, which the dataset does not support.
Press / media inquiries. Reach the Ownlisted Research team via the brand-hub contact page. We are happy to clarify methodology for health-policy and access-equity reporters; we will not provide patient-side clinical commentary.
Cited literature (suggested for follow-up reading):
- Glezer A. et al. (2025). A network-based cross-sectional study of geographic access to dermatology care. — 96.6% within-one-hour figure and 11M-underserved estimate.
- Yeh, J. et al. (2023). Dermatologist demographic density and melanoma outcomes. — Density-to-outcomes linkage; largest marginal gains at low end.
- Medscape (2026). A Potential Solution to Access Issues in Rural America. — Telemedicine and PA-led capacity-expansion pathways.
- Dermatologist Statistics Worldwide: Global Access (2026). — Comparative international density figures.
- Gravity models for potential spatial healthcare access (2023). — Methodological reference for E2SFCA and gravity-decay approaches.
Limitations
- Density is not spatial access. Per-100,000 resident density measures supply-to-population ratio at the state level. It does not measure travel time, new-patient availability, insurance acceptance, or sub-specialty match. Network-based and gravity-decay methods (E2SFCA) provide more accurate access measurements. We have not implemented those methods.
- NPPES taxonomies are self-reported. Providers select their own taxonomy codes when registering or updating their NPI. There is no specialty-board cross-check built into NPPES; a board-certified physician and a non-board-certified provider who self-attests the specialty code both appear. Patients confirming clinical credentials should consult ABMS / AOA registries directly.
- Practice Address state, not where the provider lives or practices most. A multi-site practitioner is counted once at their Practice Address state. Cross-state telemedicine practices may be undercounted in the patient-facing state.
- Active-flag accuracy. NPPES updates active/deactivated status as providers self-attest. Some providers carry stale NPIs from earlier career stages. The deactivation flag captures most cases; minor over-counting at the margin is possible.
- Census ACS 2024 vintage uncertainty. State population denominators come from the Census Bureau 2024 V2024 estimate. ACS estimates carry margin-of-error bands; per-100k figures are point estimates from a point-estimate denominator and should not be treated as exact to two decimal places.
- No procedure-mix or sub-specialty breakout. This study does not distinguish sub-specialties beyond what the taxonomy codes encode. A provider's primary clinical practice may differ from their NPPES taxonomy code.
- Type 2 (organization) NPIs excluded. Hospital-employed dermatologists who only operate under a Type 2 organization NPI are under-counted. Most dermatologists carry both, so the under-count effect is small but non-zero.
- No outcomes / quality-of-care claims. This study reports NPPES-listed counts and Census-derived densities. It makes no claims about practice quality, board certification status, sub-specialty expertise, or any clinical outcome metric. This is not medical advice. Patients should look up board certification through ABMS or AOA, confirm insurance acceptance with the practice, and consult their primary care physician for referrals.
- Snapshot in time. Counts reflect the 2026-05-06 NPPES snapshot. The cached dataset is preserved at
data/nppes/dermatology-2026-05-06.jsonfor re-analysis.
Limitations
- Density is not spatial access. Network-distance / E2SFCA / gravity methods give more accurate access measurements; we have not implemented them.
- NPPES taxonomies are self-reported; there is no specialty-board cross-check.
- Practice Address state is used; cross-state telemedicine practices may be undercounted in the patient-facing state.
- Census 2024 vintage population estimates carry margin-of-error bands; per-100k figures are point estimates from a point-estimate denominator.
- Fonteum does not rate, certify, or guarantee any provider. Patients should consult ABMS / AOA registries for board-certification status and confirm insurance acceptance with the practice directly.
Methodology
Read the full methodology
Data sources. This study uses two public datasets:
- U.S. CMS NPI Registry (NPPES) — public API at
https://npiregistry.cms.hhs.gov/api/?version=2.1, snapshot 2026-05-06. - U.S. Census Bureau Population Estimates Program (PEP) — 2024 Vintage (V2024) state population estimates, released 2024-12-19.
Inclusion criteria. Each provider counted meets all of:
- NPI Type 1 (individual practitioner) — Type 2 (organization) NPIs are excluded.
basic.status = "A"andbasic.deactivation_dateis null.- Carries at least one of the 5 Dermatology Healthcare Provider Taxonomy codes:
207N00000X(Dermatology (parent)),207ND0900X(Dermatopathology),207NI0002X(Clinical & Laboratory Dermatological Immunology),207NP0225X(Pediatric Dermatology),207NS0135X(Procedural Dermatology / MOHS). - Has a U.S. Practice Address (LOCATION). Mailing-only addresses are not used.
State assignment. Providers are bucketed by their Practice Address state, not their Mailing Address state. Each NPI is counted once.
Density computation. Per-100,000 figures are: (count / Census 2024 vintage population) × 100,000. Underserved threshold: less than 4 active dermatologists per 100,000 residents. Transparent baseline cutoff that sits roughly at the lower bound of access-gap thresholds reported in the 2023 spatial-access literature and the AAMC dermatology workforce reports. Stated explicitly here; not a clinical or regulatory definition.
What density does not measure. Per-100k density is a supply-to-population ratio at state granularity. It does not measure spatial access, new-patient availability, insurance acceptance, sub-specialty match, board-certification status, or any quality / clinical-outcomes metric. Network-distance and gravity-model approaches (E2SFCA) provide more accurate geographic-access measurements and are explicitly cited above; this study does not implement them.
Differentiation. This is a public-records-only study. The downloadable CSV and JSON preserve NPI numbers and per-state aggregates so any reader can audit individual records against the live NPPES registry. Fonteum does not independently rate, inspect, certify, or guarantee any provider — the label "active in NPPES" describes a CMS registry status, not a quality attestation.
Not medical advice. Patients should consult ABMS / AOA registries for board-certification status, confirm insurance acceptance with the practice directly, and discuss referrals with their primary care physician.
Reproducibility. The cached NPPES dataset at data/nppes/dermatology-2026-05-06.json and the per-state aggregate at public/research/data/derm-supply-by-state-2026-05-06.json (also CSV) are the canonical snapshots. The ingestion script and aggregation script are version-controlled under scripts/research/.
Data sources. This study uses two public datasets:
- U.S. CMS NPI Registry (NPPES) — public API at
https://npiregistry.cms.hhs.gov/api/?version=2.1, snapshot 2026-05-06. - U.S. Census Bureau Population Estimates Program (PEP) — 2024 Vintage (V2024) state population estimates, released 2024-12-19.
Inclusion criteria. Each provider counted meets all of:
- NPI Type 1 (individual practitioner) — Type 2 (organization) NPIs are excluded.
basic.status = "A"andbasic.deactivation_dateis null.- Carries at least one of the 5 Dermatology Healthcare Provider Taxonomy codes:
207N00000X(Dermatology (parent)),207ND0900X(Dermatopathology),207NI0002X(Clinical & Laboratory Dermatological Immunology),207NP0225X(Pediatric Dermatology),207NS0135X(Procedural Dermatology / MOHS). - Has a U.S. Practice Address (LOCATION). Mailing-only addresses are not used.
State assignment. Providers are bucketed by their Practice Address state, not their Mailing Address state. Each NPI is counted once.
Density computation. Per-100,000 figures are: (count / Census 2024 vintage population) × 100,000. Underserved threshold: less than 4 active dermatologists per 100,000 residents. Transparent baseline cutoff that sits roughly at the lower bound of access-gap thresholds reported in the 2023 spatial-access literature and the AAMC dermatology workforce reports. Stated explicitly here; not a clinical or regulatory definition.
What density does not measure. Per-100k density is a supply-to-population ratio at state granularity. It does not measure spatial access, new-patient availability, insurance acceptance, sub-specialty match, board-certification status, or any quality / clinical-outcomes metric. Network-distance and gravity-model approaches (E2SFCA) provide more accurate geographic-access measurements and are explicitly cited above; this study does not implement them.
Differentiation. This is a public-records-only study. The downloadable CSV and JSON preserve NPI numbers and per-state aggregates so any reader can audit individual records against the live NPPES registry. Fonteum does not independently rate, inspect, certify, or guarantee any provider — the label "active in NPPES" describes a CMS registry status, not a quality attestation.
Not medical advice. Patients should consult ABMS / AOA registries for board-certification status, confirm insurance acceptance with the practice directly, and discuss referrals with their primary care physician.
Reproducibility. The cached NPPES dataset at data/nppes/dermatology-2026-05-06.json and the per-state aggregate at public/research/data/derm-supply-by-state-2026-05-06.json (also CSV) are the canonical snapshots. The ingestion script and aggregation script are version-controlled under scripts/research/.
Technical appendix
Show technical details · script paths · field names
Ingestion. scripts/research/nppes-by-taxonomy-ingest.ts dermatology paginates the NPPES public API per state × per dermatology-taxonomy-description. The API caps any single query at 1,200 results (skip 0..1000, limit 200). For state×taxonomy combinations that saturate the cap, the script falls back to a recursive ZIP-prefix split: 100 two-digit prefixes per saturated query, recursing to three-digit prefixes if needed. Results are deduplicated by NPI across taxonomy queries and ZIP-prefix splits.
Filters applied at ingestion.
enumeration_type === "NPI-1"(individual practitioners)basic.status === "A"ANDbasic.deactivation_dateis nulladdresses[].address_purpose === "LOCATION"ANDcountry_code === "US"(Practice Address)- At least one taxonomy code in {207N00000X, 207ND0900X, 207NI0002X, 207NP0225X, 207NS0135X}
Aggregation. scripts/research/specialty-supply-aggregate.ts dermatology reads the cached NPPES JSON and the static scripts/research/census-state-pop-2024.json (Census 2024 V2024 estimates). For each state it computes count, per-100k density, density rank, count rank, quartile-by-density, and the underserved flag. Output:
public/research/data/derm-supply-by-state-2026-05-06.json— full row-level dataset + summary metadatapublic/research/data/derm-supply-by-state-2026-05-06.csv— same data in CSV form
Chart. scripts/research/build-specialty-supply-chart.ts dermatology emits the hand-coded SVG at public/research/charts/dermatology-provider-supply-by-state-2026/state-ranking-by-density.svg. Palette pulled from src/lib/research/chart-theme.ts (§133). No charting library; no Plotly defaults.
Doctrine references. §95 (NPPES ingestion), §126 (newsroom + AI-citation readiness), §181 (NPPES dermatology supply by state — first full-source-enumeration study), §182 (specialty-study factory — this study generated through the factory).
Open for the script paths, raw dataset filenames, and per-field aggregation rules behind this snapshot. Reader-facing methodology above already covers source, date, and limitations.
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