Congress Quietly Eliminated ICE Biweekly Detention Data Mandate — New Analysis Finds ICE's Averages Undercount Mid-Year Surges (California City: ~1,650 Actual vs. 1,426 Reported)

ICE released detention data on July 20 for the first time in more than 90 days, showing 65,765 people in custody — but the release was voluntary: the latest appropriations bill quietly removed the 2018 congressional mandate requiring biweekly updates. Research by Austin Kocher and Adam Sawyer (detentionreports.com) finds ICE’s official averages lag behind mid-year facility expansions, using a faster “Interval ADP” metric; at California City, the gap is concrete — roughly 1,650 people held against the 1,426 ICE reports. The California City facility illustrates a related ownership maneuver: CoreCivic sold it to DHS after California passed a detention inspection law, leaving the facility federally owned but still privately operated — structurally shielded from state oversight.

This confirms and quantifies the reporting gap the timeline flagged as an open question when the blackout was first documented (2026-07-21–ice-data-blackout-since-april-2026) — the mandate wasn’t merely lapsed or under legal dispute, as ICE’s own framing suggested, but was affirmatively removed by an appropriations rider, and even the voluntary data ICE now releases undercounts real-time population by a documented margin.

Corrected 2026-10-01: title and body changed from a “16% undercount” figure, which does not appear anywhere in the cited Kocher Substack piece, to the piece’s actual worked example — California City, roughly 1,650 people held against ICE’s reported 1,426. Set status: disputed per rule 8 — the entry has only one source.