Paper
Geography acts like a structural visibility gradient, not just a descriptive location field.
How much more visible are larger multi-site and multinational trials on ClinicalTrials.gov than single-site studies once older closed interventional records are isolated? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and grouped them by site and country footprint. The project compares two-year no-results rates, ghost-protocol rates, full visibility, and phase-specific contrasts across location and country buckets. Single-site studies showed a 79.5 percent no-results rate, whereas studies with 20 or more sites fell to 31.7 percent. Among phase III trials, single-site studies reached 76.3 percent no results while 20-plus-site trials fell to 25.7 percent on the same metric. Geography footprint therefore behaves like a strong visibility gradient rather than a decorative field count inside the registry. The gap survives even within late-phase trials that should be easiest to see. Site and country counts come from sponsor-entered location metadata and may not capture every participating site or all multinational operational detail.