Our Methodology

Medical Disclaimer: PlainTrial provides information for educational purposes only. Nothing on this site constitutes medical advice. Always consult your healthcare provider before making any health decisions, including decisions about clinical trial participation.

Data Source

All clinical trial data comes from ClinicalTrials.gov, a service of the U.S. National Institutes of Health (NIH) / National Library of Medicine (NLM). ClinicalTrials.gov is the official registry of publicly and privately supported clinical studies conducted in the United States and around the world, mandated by the FDA Amendments Act of 2007.

The global registry held 597,691 registered studies when we last checked it against the ClinicalTrials.gov API on 8 August 2026, covering all therapeutic areas, interventional and observational designs, and every phase from Phase 1 through Phase 4 and post-marketing surveillance. PlainTrial indexes a focused subset of that registry: 175,638 US-based trials across all phases and condition categories, from the 2026-07-11 snapshot. We keep the five statuses a reader can act on or learn from - Recruiting, Active (not recruiting), Completed, Terminated and Not Yet Recruiting - and leave out Withdrawn and Suspended studies, which never enrolled or have stopped enrolling with no reported outcome.

Data Download and Processing

We download the ClinicalTrials.gov bulk data export, which is available as JSON-formatted records for each registered study. For each trial, we extract and index:

  • Study title, official title, and brief summary
  • NCT identifier (the unique ClinicalTrials.gov study ID)
  • Study status (Recruiting, Active, Completed, Terminated, etc.)
  • Phase (Phase 1, 2, 3, 4, N/A)
  • Primary sponsor and collaborating organizations
  • Condition or disease area
  • Intervention type and names
  • Eligibility criteria (age range, sex, healthy volunteers)
  • Study locations (facility, city, state, country)
  • Start date and estimated completion date
  • Primary and secondary outcome measures
  • Participant recruitment target

Search and Indexing

We build a full-text search index over trial titles, summaries, conditions, interventions, and sponsor names to enable fast keyword searches across the entire database. Location data extracted from study site records enables geographic filtering by state and city, allowing patients and researchers to find trials near their location. Condition categories and intervention types provide structured browsing beyond free-text search, organized into major therapeutic areas for easy navigation.

Data Collection Method

ClinicalTrials.gov receives study records directly from sponsors and investigators. Under the FDA Amendments Act of 2007, sponsors of applicable clinical trials are legally required to register their studies and submit results. Many other sponsors (academic institutions, NIH-funded researchers) register voluntarily. Each study record is submitted by the responsible party and undergoes automated quality checks by the NLM before publication. The resulting registry contains studies across all therapeutic areas, phases, and study designs. We download the bulk data export, which contains the full text of each study record in structured JSON format.

Update Schedule

ClinicalTrials.gov is updated continuously as sponsors submit new registrations and update existing records. Our database is refreshed from bulk data exports; the snapshot currently on this site is from 2026-07-11. Between refreshes, newly registered trials and status changes (e.g., a trial changing from "Recruiting" to "Completed") will not be reflected. For the most current trial information, always check ClinicalTrials.gov directly.

Corpus placement (rank and tier bands)

Condition, state, and sponsor pages state where the entity sits in PlainTrial's own indexed corpus, a derived signal, not a restatement of a ClinicalTrials.gov field. Rank is 1 + count of peers with a strictly higher trial_count among rows with trial_count > 0. Named tier bands (so sibling pages diverge after digit normalization) use those ranks against the live corpus size:

  • top decile - rank ≤ 10% of the corpus
  • upper quartile - rank ≤ 25%
  • upper half - rank ≤ 50%
  • lower half - everyone else

Ties on identical trial_count share the same denser-count floor (standard competition ranking). Tiers are recomputed from the current database on every page render, they are not hand-picked lists.

Limitations

  • Data may not reflect real-time updates from ClinicalTrials.gov, there is a lag between our snapshot and the live database.
  • Trial status, eligibility requirements, and participant availability can change after our data snapshot.
  • Not all trials are fully compliant with ClinicalTrials.gov mandatory reporting requirements, some records may be incomplete.
  • International trials listed on ClinicalTrials.gov are included but may have limited location data.
  • Contact information for trial sites may be outdated; always verify directly with the listed facility.
  • Condition names are recorded directly as investigators entered them on ClinicalTrials.gov, which is not a fully standardized vocabulary - the same underlying condition can appear under multiple wordings (for example "HIV Infections" and "HIV-1 Infection"), and each variant is tracked as a separate condition page rather than automatically merged. Rankings and condition counts reflect this per-wording basis, not a clinically de-duplicated total.

Always verify current trial information directly at ClinicalTrials.gov before making any decisions about participation.

Corrections and changelog

If a figure on this site looks wrong, use report a data issue (include the page URL, the field, what you believe is correct, and a link to the ClinicalTrials.gov record). We compare the claim against the published registry export, fix pipeline-side errors at the source so every affected page updates together, and leave registry-faithful values alone while pointing you to ClinicalTrials.gov when the upstream record is the issue. Expected turnaround for an acknowledgment is within a few business days; upstream registry corrections land on our next refresh. Material publisher-side corrections and methodology revisions are listed on the data & editorial changelog. The full process is on editorial policy.

Not Affiliated

PlainTrial is not affiliated with the NIH, NLM, FDA, or any government agency. We are an independent portal that makes ClinicalTrials.gov data more accessible.