The published files suppress individual cells, not whole cohorts, and the categories sum to the cohort — so on 22% of mainstream secondaries the withheld figure can be recovered by subtraction. Three disclosure rules fall out of that, and the rest of the design is downstream of them. Verified against the EES API rather than assumed: both datasets carry school-level rows keyed by URN, with the disadvantage split and every destination category the display needs. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BvdDKvFFSZuMVDH5fEyTob