Source-specific identities. Evidence-backed links.
NPPES uses NPIs. PECOS uses enrollment identifiers and NPI where published. CMS Care Compare primarily uses CCNs. OIG LEIE often lacks NPI, and HRSA uses its own identifiers. Fonteum links records only when the source identifiers and match evidence support that relationship; an NPI is not forced onto sources that do not carry it.
0providers canonically linked across 5 identity-graph datasets·0high-confidence links·methodology —·last extended —
Verifier reference + code samples → Cryptographic chain → Snapshot integrity →
Company-register sources stay separate from healthcare identifiers.
Identifier definitions: ABN, DUNS number, and Legal Entity Identifier. Each belongs to a different source system and must not be treated as an interchangeable key.
Public endpoints default to high (≥ 0.9) only.
No identity links yet. The linker runs every 5 minutes against the NPPES specialty caches + 4 source-side tables (pecos_providers, carecompare_providers, leie_providers, hrsa_providers). All 4 source tables ship empty; once Cowork backfills normalize source_snapshots payloads into them, the linker will begin producing links and this chart will populate.
Nine strategies across 5 federal sources, confidence-ordered.
NPPES ↔ PECOS
exact_npi_in_pecos· confidence 1.0
PECOS row carries an explicitnpimatching an NPPES record. Strongest possible link.exact_name_address· confidence 0.95
Normalized provider name AND byte-equal normalized address. Not 1.0 because group practices can share an office.name_address_fuzzy· confidence 0.7-0.9
Jaro-Winkler similarity, gated by exact state + zip5. Fuzzy ceiling 0.9 — public default (≥ 0.9) excludes bottom of fuzzy band.
NPPES ↔ Care Compare CCN
exact_npi_in_carecompare· confidence 1.0
Care Compare row carries an NPI matching the NPPES record.exact_name_address_carecompare· confidence 0.95
Facility name + byte-equal address. No fuzzy strategy — Care Compare facility names have high lexical variance; deferred to Phase 3.
NPPES ↔ OIG LEIE
exact_npi_in_leie· confidence 1.0
A LEIE row that publishes NPI matches the NPPES record exactly; most LEIE rows do not carry one.name_dob_leie· confidence 0.95
Legacy LEIE rows (pre-NPI-era exclusions). Normalized name AND identical DOB. No fuzzy strategy — false-positive cost too high for exclusion claims.
NPPES ↔ HRSA HPSA
exact_npi_in_hrsa· confidence 1.0
HRSA HPSA row carries an NPI matching the NPPES record.
Operator-asserted
manual· confidence 1.0
Operator-asserted via direct SQL. Used for high-value disputed records. UI for self-service operator curation deferred to Phase 3.
Three reads. No credentials.
# Resolve an NPI to its canonical PECOS-ID
curl https://fonteum.com/api/v1/identity/nppes/1245319599
# Resolve a PECOS-ID to its canonical NPI
curl https://fonteum.com/api/v1/identity/pecos/PAC-100001
# Aggregate stats: total linked + confidence-band distribution
curl https://fonteum.com/api/v1/identity/stats
# Opt-in to surface low-confidence (<0.9) links for diligence
curl 'https://fonteum.com/api/v1/identity/nppes/1245319599?include_low_confidence=true'Full reference + Node + Python + Go samples at /docs/identity.
Once a canonical identity layer exists and is queryable, it becomes the default reference for the category. Every Fonteum consumer (MCP server, webhook events, semantic search, future dbt package) joins against provider_identity_links, not against the federal sources directly.