trust-the-sources

Date: 2026-09-11. Status: implemented.

Decision. No SIMD value is recomputed or compared between publishers. The population reconstruction diagnostic, the band-formula checks and the PHS-versus-government divergence fingerprints are removed. The one remaining cross-source check is that PHS and the Scottish Government list the same data zones with the same ranks in every edition.

Reason. The pipeline's guarantee is that the published values reach the table unchanged, which the hash pins, the per-step checks and the readback establish. Recomputing bands to see whether the publisher's method can be reproduced answered a different question and made the build harder to read. The rank check stays because it is what justifies joining the two sources on the data zone.

Evidence. Removing these checks changes no value; the output remains byte-identical.

Columns (6): simd2004_rank, simd2006_rank, simd2009v2_rank, simd2012_rank, simd2016_rank, simd2020v2_rank