`tk10873/cross_validate_feed.md`

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# TK-10873 cycle 4 — REPRICE vs independent S1 feed cross-validation

- **Verdict:** FAIL
- Source A (draft): `zoffany_catalog.price_retail`
- Source B (independent): SDG S1 feed harvest `retail_usd` (TK-10877)
- REPRICE rows: 328

## Cross-validation buckets
| bucket | count | meaning |
|---|---|---|
| CONFIRMED | 30 | feed agrees with draft (ratio ~1.0) — 2nd-source verified |
| DISCREPANT_UNIT_2_5X | 209 | feed ~2.54x the draft price — systematic unit/currency mismatch, draft may be a ~2.5x UNDERPRICE |
| DISCREPANT_OTHER | 0 | feed disagrees by some other factor |
| UNVERIFIABLE | 89 | feed has no retail for this mfr_sku — cannot 2nd-source check |
| BAD_PROPOSED | 0 | proposed price nonpositive (should be 0) |

## What this means
The ~2.54x factor (= 2 × ~1.27) is consistent with a double-roll × GBP→USD transform applied by one source and not the other. **This tool does NOT decide which is right** — it surfaces the discrepancy. The Option-A reprice of the DISCREPANT_UNIT_2_5X cohort is BLOCKED pending a Steve/pricing-owner ruling on the canonical price source (the epic TK-10874 says S1/feed is authoritative, which would make the draft's zoffany_catalog values wrong-low).

Safe-to-reprice now = CONFIRMED (30). Everything else holds.