CT.gov Publication Undercount Audit
2026-03-29 | full-registry ct.gov audit | plots, figures, and e156 bundle
Series
PubMed Audit Dashboard

Strict external PubMed rescue is uncommon among older CT.gov no-link records

The sample-based external audit suggests that CT.gov publication-link missingness is not mostly a giant under-linking artifact.

Sample rates
Weighted effect
External only
Class strata

Dashboard

A missing CT.gov publication link is not always final, but the external rescue rate here is low enough to matter.

How to read the dashboard
Weighted match
1.2%
PubMed NCT match
Weighted external only
0.3%
PubMed only
Network sample
3.3%
Highest raw sample class
Other sample
0.7%
Largest population class
Raw sample PubMed match rate
SAMPLE PUBMED AUDITRaw PubMed NCT-match rate by sponsor-class audit stratumNETWORK3.3%OTHER_GOV2.0%INDUSTRY2.0%NIH2.0%FED1.3%OTHER0.7%INDIV0.0%
No sponsor-class sample stratum looks large on the raw PubMed NCT-match metric.
The strict identifier-based audit is meant to test visible under-linking, not to serve as a broad literature review.
Weighted audit summary
WEIGHTED AUDIT SUMMARYWeighted overall PubMed rescue estimates after reweighting the sponsor-class sampleWeighted PubMed match1.2%Weighted external only0.3%Raw weighted sample1.6%
The weighted all-population rescue signal is smaller than the raw audit sample rate.
Reweighting matters because the no-link population is dominated by OTHER and INDUSTRY rather than by the smaller class strata.
Read Across Projects

Across The Series

Each project isolates a different dimension of registry opacity, but the point is the contrast between them, not a single leaderboard.

Industry
CT.gov Industry Disclosure Gap

Industry-focused missing-results stock, sponsor backlogs, and structural sparsity inside CT.gov.

Sponsor Classes
CT.gov Sponsor-Class Hiddenness

Sponsor-class comparisons on rate, stock, and structural hiddenness rather than one flattened ranking.

Phases
CT.gov Phase Reporting Gap

Phase-by-phase disclosure gaps showing how silence changes along the development pathway.

Structural
CT.gov Structural Missingness

Field-level missingness across publication links, IPD statements, descriptions, and locations.

Visibility
CT.gov Evidence Visibility Gap

Results-plus-publication visibility states showing how many older trials are fully visible, partly visible, or ghosted.

Cohorts
CT.gov Completion Cohort Debt

Completion-era reporting debt showing how older eligible cohorts drift on no-results and ghost-protocol rates.

Conditions
CT.gov Condition Hiddenness Map

Keyword-classified therapeutic-area hiddenness mapping across common condition families.

Concentration
CT.gov Sponsor Backlog Concentration

Concentration and inequality analysis showing how much unresolved stock sits inside a thin sponsor slice.

Rule Eras
CT.gov Rule-Era Reporting Gap

Policy-era comparisons across pre-FDAAA, FDAAA, and later CT.gov completion cohorts.

Oncology
CT.gov Oncology Hiddenness

Oncology-specific CT.gov hiddenness showing where cancer-trial stock, phases, and sponsors still go quiet.

Cardiovascular
CT.gov Cardiovascular Hiddenness

Cardiovascular CT.gov hiddenness showing how heart and vascular studies remain quiet across major phases and sponsors.

Metabolic
CT.gov Metabolic Hiddenness

Metabolic CT.gov hiddenness across obesity, diabetes, and related trial portfolios with large late-phase and NA stock.