Paper
Intervention family changes who looks like a chronic repeater. One sponsor table is not enough.
Which sponsors carry the biggest missing-results backlogs once older CT.gov studies are split by intervention family rather than ranked in one pooled sponsor table? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and linked sponsors to intervention-family labels from the registry extract. The project compares sponsor-level no-results counts, no-results rates, ghost-protocol rates, and visible shares within drug, device, procedure, behavioral, biological, and dietary-supplement study families. In drug studies, GlaxoSmithKline carried 1,033 missing-results studies, while Cairo University led device studies with 205 records. Procedure studies led by Cairo University reached 97.3 percent no results, Maastricht University Medical Center led dietary-supplement backlogs with 154 studies, and UCSF led behavioral backlogs with 317. Sponsor repeaters therefore change sharply by modality, meaning whole-registry rankings hide intervention-specific clusters of silence that recur inside particular treatment families. Sponsor names and intervention labels are registry-entered fields and do not adjudicate parent-company structure, collaborations, or off-platform dissemination.