Data Sources
Exactly which data sets NPISignal uses — CMS NPPES, HHS-OIG LEIE, SAM.gov and the NUCC taxonomy — which fields it takes from each, and how current each one is.
Updated
NPISignal is built entirely from four public data sets, each published by a different federal or standards body. NPISignal does not supplement, estimate, or infer any fact beyond what these sources publish.
Three of the four are bulk files NPISignal holds a copy of, so every result can state the publication date of the data it searched. The fourth, SAM.gov, is an API queried at the moment of a search — which is why a SAM result carries the time it was checked rather than a publication date.
CMS NPPES — the National Provider Identifier registry
The National Plan and Provider Enumeration System (NPPES), operated by the Centers for Medicare & Medicaid Services (CMS), is the source of every NPI, provider name, practice location, and taxonomy assignment on NPISignal. See What Is NPPES? for how the system itself works.
| Fact NPISignal shows | NPPES field(s) it comes from |
|---|---|
| NPI, entity type (individual/organization) | NPI, Entity Type Code |
| Display name | Provider Last/First/Middle/Prefix/Suffix Name, or Provider Organization Name |
| Credential (e.g., MD, DO, NP) | Provider Credential Text |
| Sole proprietor / organization subpart | Is Sole Proprietor, Is Organization Subpart |
| Practice address and phone | Provider Business Practice Location Address fields |
| Other reported names | Other Name Reference File (othername_pfile) |
| Secondary practice locations | Practice Location Reference File (pl_pfile) |
| Enumeration date, last update date | Provider Enumeration Date, Last Update Date |
| Active / deactivated status | NPI Deactivation Date, NPI Reactivation Date |
| Taxonomy (specialty) codes, up to 15 per NPI, and which is primary | the taxonomy code block, including the Primary Taxonomy Flag |
| Provider-reported license number and state | the license number/state paired with each taxonomy code |
NPISignal does not use the Endpoint Reference File (electronic endpoints) or the Other Provider Identifier block (legacy payer-assigned identifiers) in this version of the site.
HHS-OIG LEIE — the exclusion list
The List of Excluded Individuals/Entities (LEIE), published by the HHS Office of Inspector General, is the source for the single exclusion fact NPISignal ever shows on a profile: whether an active LEIE record names that exact NPI. See What Is the OIG Exclusion List? for what an exclusion actually means.
| Fact NPISignal shows | LEIE column it comes from |
|---|---|
| Name of the excluded party | LASTNAME, FIRSTNAME, MIDNAME, or BUSNAME |
| General category and specialty | GENERAL, SPECIALTY |
| Statutory authority for the exclusion | EXCLTYPE |
| Exclusion, reinstatement and waiver dates | EXCLDATE, REINDATE, WAIVERDATE, WVRSTATE |
| Location on record | ADDRESS, CITY, STATE, ZIP |
| NPI, where OIG holds one | NPI |
| Whether a date of birth exists — never the value | DOB |
Why a provider profile is narrower than the search
Dates of birth
SAM.gov — federal exclusions and debarment
SAM.gov carries the government-wide record of parties excluded from federal procurement and non-procurement programs, maintained by the General Services Administration and populated by many agencies. NPISignal reads it through the official Exclusions API rather than holding a copy — there is no bulk file to import. See SAM.gov exclusions explained for how it differs from the LEIE.
| Fact NPISignal shows | Where it comes from |
|---|---|
| Classification (individual, firm, vessel, special entity) | exclusionDetails.classificationType |
| Name | exclusionIdentification.entityName, or firstName / lastName |
| Exclusion type and program | exclusionDetails.exclusionType, exclusionProgram |
| Excluding agency | exclusionDetails.excludingAgencyName |
| UEI and CAGE code | exclusionIdentification.ueiSAM, cageCode |
| Location | exclusionPrimaryAddress |
| Activation and termination dates | exclusionActions.listOfActions |
What is deliberately not collected
NUCC — the provider taxonomy code set
The Health Care Provider Taxonomy, maintained by the National Uniform Claim Committee (NUCC), supplies the label, grouping, classification, and definition shown for every specialty code. See What Are Healthcare Provider Taxonomy Codes? for how the code set itself is structured.
Publication and import cadence
| Source | Publisher's cadence |
|---|---|
| NPPES full file | Monthly, full replacement |
| NPPES weekly file | Weekly, incremental |
| LEIE | Monthly, full replacement plus a monthly supplement |
| SAM.gov exclusions | Continuous — an API, not a published file |
| NUCC taxonomy | Twice yearly (January release effective April 1; July release effective October 1) |
NPISignal's dataset in use right now: NPPES August 2026, imported August 21, 2026; LEIE dataset dated September 10, 2026, imported September 16, 2026; NUCC taxonomy version 26.1. Provider counts currently indexed: 9,447,072 total, 9,443,430 active. LEIE records loaded: 84,001.
Known limitations
- All three sources are as current as their publisher's own release, not real time. A change a provider makes in NPPES today is not reflected on NPISignal until CMS's next file and NPISignal's next import.
- NPPES is self-reported. CMS does not independently verify a provider's address, phone number, or license number against any outside system, and NPISignal republishes exactly what NPPES reports.
- NPPES's public file does not disclose the reason an NPI was deactivated, only that it was and when.
- An organization's EIN and a subpart's parent-organization tax ID are suppressed by CMS in the public file and are not available to NPISignal.
- A provider profile shows an LEIE record only on an exact NPI match, and many LEIE entries — particularly older ones — carry no NPI at all. Those records are still searchable by name on the exclusion search tools; they simply cannot be attached to a provider profile.
- Neither the LEIE nor SAM.gov contains a Social Security number or an employer identification number, so where two people share a name and a date of birth the public data cannot separate them. HHS-OIG operates its own verification process for that situation and it is the authoritative route.
- SAM.gov publishes neither a date of birth nor an NPI, so a SAM name match rarely has anything available to corroborate it.
- State Medicaid exclusion lists are not covered. Most states maintain one, and many state and payer contracts require screening against them separately.
- NUCC taxonomy codes are self-selected by the provider at the time of application or update, not independently verified against board certification.
NPI Files — the NPPES download index CMS maintains — CMS
Exclusions Database — the LEIE's own online search and downloads — HHS Office of Inspector General
SAM.gov Exclusions — the official search — U.S. General Services Administration
Exclusions API documentation — the endpoint NPISignal queries — U.S. General Services Administration
NUCC Health Care Provider Taxonomy — the official code set — National Uniform Claim Committee