Paper
A fast study cycle does not translate into a fast public record.
Does ClinicalTrials.gov hiddenness fall as trials take longer from first submission to completion, or do short-cycle studies report just as well? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and calculated submission-to-completion delay buckets. The project compares two-year no-results rates, ghost-protocol rates, full visibility, and purpose-specific contrasts across registration-to-completion intervals. Studies completed in the same calendar year they were first submitted showed an 85.7 percent no-results rate and a 54.1 percent ghost-protocol rate. Studies with a 6 to 10 year delay fell to 57.6 percent no results and 28.8 percent ghost protocols, with long-lag treatment studies also looking substantially cleaner. Fast-cycle studies therefore look most hidden, suggesting short operational timelines are not translating into faster public reporting. The contrast remains visible across treatment studies and other major purpose groups. Submission-to-completion lag is a registry proxy for operational duration and can reflect backfilled dates, protocol amendments, or changing trial mix.