Paper
Other and Industry dominate endpoint-only stock, but NIH and Network are much sharper on rate once class size is taken into account.
Which sponsor classes most often leave older CT.gov study pages without the primary outcome description while keeping the broader detailed-description field? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and grouped them by lead sponsor class. We defined a primary-only gap as missing primary outcome description with detailed description still present, then compared sponsor-class stock, rate, and text-balance context. The Other class led sponsor-class primary-only-gap stock at 21,381 studies, followed by Industry at 7,906, NIH at 1,258, and Other Gov at 729. NIH had the highest substantive sponsor-class primary-only-gap rate at 29.4 percent, while Network reached 21.2 percent and Indiv 20.5 percent. The sponsor-class view shows that endpoint-only text gaps are not spread evenly: NIH and network portfolios are much sharper on rate, while Other and Industry dominate on stock. Sponsor classes are broad registry buckets and should be read as portfolio patterns rather than judgments about single studies.