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ClinicalTrials.gov

ClinicalTrials.gov Studies

U.S. National Library of Medicine (ClinicalTrials.gov) · Tier-1 · research-only (never on individual profiles)

Research-only
Source:ClinicalTrials.gov·Snapshot May 2026Open official source ↗

ClinicalTrials.gov is the U.S. National Library of Medicine's registry of interventional and observational clinical studies. It records sponsors, principal investigators (overall officials), conditions, interventions, and study status. As of the 2026-06-14 snapshot, Fonteum holds 555,500 registered studies.

What Fonteum uses it for

How this source shows up on Fonteum.

Tier-1 research-only context for studies on research activity and key-opinion-leader networks. Fonteum surfaces study title, status, conditions, sponsor, and overall officials at the aggregate level. Records are name-keyed (PIs and sponsors by name / affiliation); there is no NPI in the source, and NPI / entity-graph linkage is deferred — ambiguous matches are held.

What this source does NOT mean

A ClinicalTrials.gov record describes a registered study — it does not measure provider quality, outcomes, or endorsement, and a named investigator is not a Fonteum-asserted identity match to any specific provider profile. Registration does not imply a result, an approval, or a Fonteum assessment.

What this dataset answers

Research and data questions this source supports.

  • 01Build a research dataset of registered clinical studies by condition, sponsor, or status with row-level provenance.
  • 02Analyze research-activity and key-opinion-leader networks at the aggregate, name-keyed level.
  • 03Track interventional and observational study volume by condition area over time.
  • 04Feed a retrieval system with structured study records (NCT id, title, status, sponsor) and source attribution attached.

Dataset size: 555,500 registered studies (2026-06-14 snapshot)

Fields used

Per-field display contract.

Every field below has a `display_allowed` flag in the §94 provenance schema. Write-locked fields are captured to provenance for audit but never rendered on profile pages.

Research-only — never on profiles

5 fields
nct_idNCT registration number
titleStudy title
overall_statusOverall status
sponsorLead sponsor (by name)
overall_officialsOverall officials / PIs (by name)
Limitations

What we can’t infer from this source.

  • Tier-1 — aggregate research context only; never rendered on individual provider profiles.
  • Name-keyed: investigators and sponsors are recorded by name / affiliation. There is no NPI in the source.
  • NPI / entity-graph linkage is deferred; ambiguous name matches are held, not written.
  • Registration is self-reported by sponsors and may lag or omit results.
Source metadata

Authority, license, refresh cadence.

Authority

U.S. National Library of Medicine (ClinicalTrials.gov)

Tier

Tier-1 · research-only (never on individual profiles)

Refresh cadence

Monthly — pulled from the ClinicalTrials.gov Data API v2; Fonteum re-pulls on snapshot publication.

License

Courtesy of the U.S. National Library of Medicine. Public-domain federal data; free to use with attribution. License ↗

Official URL

https://clinicaltrials.gov

Attribution requirement

Courtesy of the U.S. National Library of Medicine (ClinicalTrials.gov) · Snapshot {YYYY-MM-DD}

ToS & usage notes

What the source allows.

Courtesy of the U.S. National Library of Medicine (ClinicalTrials.gov). The Data API v2 is key-less and public-domain; the only ask is the NLM courtesy attribution. Fonteum pulls study-level records and attests each snapshot.

Sample provenance

What a single field looks like in the graph.

A worked example. Every field surfaced from this source carries this shape of provenance line — source · last checked · display rule · confidence (when applicable).

Field

Registered study (research-only)

Sample value

NCT00000000 · Recruiting · Lead sponsor: Example University

Provenance line

Source: ClinicalTrials.gov · Snapshot 2026-06-14 · Methodology clinicaltrials-gov/v1 · Display rule: name-keyed research context — never an asserted provider-identity match

How to access

Official API, bulk download, and Fonteum endpoints.

Official API / download

https://clinicaltrials.gov/data-api/api ↗

Fonteum surface

https://fonteum.com/api/v1/clinical-trials/{nct} →

Frequently asked

Common questions about ClinicalTrials.gov.

What is ClinicalTrials.gov?
ClinicalTrials.gov is the U.S. National Library of Medicine's public registry of interventional and observational clinical studies conducted around the world. Each record carries an NCT registration number, study title, status, conditions, interventions, sponsor, and overall officials (principal investigators).
How does Fonteum source ClinicalTrials.gov data?
Fonteum pulls study-level records from the ClinicalTrials.gov Data API v2, which is key-less and public-domain. Records are re-pulled monthly and each snapshot is attested. As of the 2026-06-14 snapshot, Fonteum holds 555,500 registered studies.
Are study investigators linked to provider profiles?
No. ClinicalTrials.gov records are name-keyed — principal investigators and sponsors are recorded by name and affiliation, and there is no NPI in the source. NPI / entity-graph linkage is deferred; a named investigator is not a Fonteum-asserted identity match to any specific provider profile.
Does a registered study mean a result or an approval?
No. Registration records that a study exists — it does not imply a result, a regulatory approval, or a Fonteum assessment. Registration is self-reported by sponsors and may lag or omit results.
How can I cite this data?
Use the NLM courtesy attribution: 'Courtesy of the U.S. National Library of Medicine (ClinicalTrials.gov)'. The data is public-domain federal data; the only ask is that courtesy attribution.
Related

Where this source already shows up.

Related sources in the graph

  • /sources/nih-reporter-projects →
  • /sources/cms-qpp-mips →
  • /sources/nppes →
See also
  • /sources → The full source library — every dataset Fonteum cites.
  • /data-provenance → The provider graph — pipeline diagram, source-family clusters, field-level provenance examples, display rules.
  • /methodology → Network-wide sourcing, refresh cadence, and corrections policy.
  • /editorial-policy → Independence, sourcing, conflicts, corrections, retractions.

The substrate, by the numbers

9.2Mgraph entitiesProviders, organizations, owners, and facilities
15.7Mlinked identifiersNPIs, CCNs, LEIs and more, resolved to entities
5Mgraph edgesSource-attested relationships between entities
44federal source familiesDistinct CMS, OIG, HRSA, FDA and peer datasets
35dataset pagesCitable, downloadable /data catalog pages
56reproducible studiesEach shipping the SQL behind its figures

Built on the authoritative federal record

The primary sources, named on every page.

These are the federal agencies whose public datasets Fonteum ingests and attributes — the issuing authorities, not customers or partners. Every figure on the site links back to one of them.

  • CMS
  • HHS-OIG
  • HRSA
  • FDA
  • NLM
  • NUCC
  • Census
  • BLS
  • BEA

See the full source registry, with license and refresh cadence for each →

Reproducible by design

Every figure traces to its federal source.

14-tuple provenance

Every rendered fact ties to a source URL, dataset ID, snapshot date, row key, and SHA-256 — the full chain-of-custody record.

Reproducible SQL

Each study ships the exact query behind its figures, run against the cited federal snapshot. Re-run it yourself.

Daily reconciliation

Published counts are reconciled against the upstream federal datasets on a daily cadence, with drift logged.

Named medical review

Reviewed by Jennifer Montecillo, MD, medical reviewer. Non-practicing medical reviewer.

Read the full provenance and attestation methodology →

Two doors

Use the free API and open data

Query providers, facilities, sanctions, and quality scores — each field carrying its federal source. Self-serve, no call to start.

Explore the API →Browse the data catalog →

Talk to us

Managed pilots, enterprise terms, and audit-ready, signed attestation packages for compliance, risk, and research teams.

Talk to us →
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Reviewed by Jennifer Montecillo, MD, medical reviewer. Non-practicing medical reviewer.

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