large-user-geography-attached

Date: 2026-09-10. Status: implemented.

Decision. SIMD is attached to every large-user record, including PO boxes, because the directory assigns them a data zone. This is ingestion source fidelity, not a claim about residence eligibility. Default SSPL SQL preserves own-record values and flags address concerns; legacy SPD SQL follows links. Python keeps its own-record geography and sentinel exclusion. See sspl-direct-sql-both-publishers.

Reason. Source fidelity. The build attaches what the directory says; it does not decide which postcodes deserve a value.

Evidence. PHS deprivation guidance v3.5, Appendix A.