CT.gov Country Excess Watchlist

Paper

Which country-linked CT.gov portfolios remain most opaque after visible study mix is held more constant? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and exploded named-country links. We summed adjusted no-results excess, adjusted ghost excess, black-box stock, and strict-core spillover across country-linked study portfolios with at least 500 linked studies. France carried the largest country-linked adjusted excess no-results stock at 2,187 studies, followed by China at 1,299 and Egypt at 824. China and Egypt also showed large ghost excess, while South Korea reached a 21.2 percent black-box rate and France still carried 3,093 black-box studies. The geography story therefore mixes large Western institutional stock with sharper hiddenness tails in several Asian and Middle Eastern portfolios once adjusted stock, ghost excess, and black-box depth are read together. Country watchlists count country-linked studies rather than assigning each study to only one nation, so multinational records can contribute to multiple national portfolios.