Paper
A later policy era does not automatically mean a cleaner public record.
Did ClinicalTrials.gov completion cohorts become more transparent after FDAAA 801 and the Final Rule? We analysed 249,507 older closed interventional studies from the March 29, 2026 full-registry snapshot and grouped them into four completion eras anchored to reporting-rule landmarks. For each era we estimated two-year no-results rates, ghost-protocol rates, no-publication rates, and the share with both results and publication visible. The FDAAA 801 era from 2008 to 2016 showed a 67.1 percent no-results rate, whereas the recent eligible era from 2021 to 2024 rose to 77.0 percent. Ghost protocols likewise increased from 39.6 percent in the FDAAA 801 era to 46.7 percent in the recent eligible era, while full visibility fell to 10.8 percent. Later eligible cohorts therefore do not look cleaner on these registry-visible measures even after each included study had at least two years to report. These policy-era comparisons are descriptive and do not adjudicate applicable-clinical-trial status or legal compliance within this registry frame.