Usable with a quick edit11 of 14 checks passed
The core recommendation, evidence, and region-by-region logic are solid. A PM could add a monitoring threshold and review date with a quick edit without redoing any analysis.
Output
Recommendation: No-go for the all-region rollout on 2 November
Do not enable auto-substitutions anywhere on 2 November: the dietary hard filter is not scheduled to deploy until 4 November, so the zero-mismatch safety criterion is not yet protected. After deployment and validation, North West is the only region I’d consider enabling first, with conditions. Hold the other regions for the reasons below.
Figures are for 1–28 October; refund rates are per 1,000 orders. Basket averages are order-weighted within each region. I excluded the three exact duplicate North West treatment rows on 8, 9 and 10 October.
| Region | Treatment acceptance (≥80%) | Refunds / 1,000 orders: treatment vs control (treatment ≤10% higher) | Dietary/allergen mismatches (must be zero) | Average basket: treatment vs control (must not be lower) | Decision |
|---|---|---|---|---|---|
| --- | ---: | ---: | --- | ---: | --- |
| London | ~86% Pass | ~17.9 vs ~18.4; Pass | 1; Fail — nut-containing bar substituted for nut-free item | ~£72.8 vs ~£72.5; Pass | No-go |
| South East | ~85% Pass | ~17.8 vs ~17.9; Pass | 1; Fail — dairy cheese substituted for vegan cheese | ~£66.6 vs ~£66.3; Pass | No-go |
| Midlands | ~86% Pass | ~17.6 vs ~18.0; Pass | 1; Fail — standard loaf substituted for gluten-free loaf | ~£55.6 vs ~£55.4; Pass | No-go |
| North West | ~86% Pass | ~17.8 vs ~18.8; Pass | 0 observed; Pass in test | ~£57.5 vs ~£57.3; Pass | Go with conditions, after filter validation |
| Scotland | ~79% Fail1 | ~29.8 vs ~18.4; Fail — about 62% higher | 0 observed; Pass in test | ~£53.0 vs ~£52.6; Pass | No-go |
Conditions and rationale
- North West: After the hard filter deploys, pass regression tests across all six protected attributes (gluten-free, vegan, vegetarian, nut-free, halal and kosher); then enable regionally with close monitoring and a rollback switch. The export duplicates should also be fixed or guarded against before relying on daily reporting.
- London, South East and Midlands: Do not launch until the filter is deployed and the dietary-mismatch failures are investigated and validated as fixed. Their good acceptance, refund and basket figures do not offset a safety-criterion failure.
- Scotland: Hold until the supplier catalogue re-map is complete and verified, and a fresh test meets both acceptance and refund guardrails. The sharp rise in treatment refunds and lower acceptance coincide with the dairy supplier/catalogue change; the issue is open, with no completion date.
The pooled “£4 smaller” basket claim should not drive this decision: treatment exposure differed by region, and baskets vary substantially by region. Within each region, the treatment average is slightly higher in these data. Likewise, an overall acceptance or refund result cannot override region-level launch gates. The 9 November booking window is important, but it does not justify launching before the safety control is live.
What a PM had to fix
1Invented evidenceVerify or remove the claimTargeted repair
What we’d change82.76%: Pass over 1–28 October. However, acceptance fell to 79.08% over 15–28 October after the supplier change, below the launch threshold.
Grades and run details
Decision model 79 · LLM judge 87
Decision model checks
- passUses the supplied evidence correctly10%
- passAddresses the actual decision46%
- passRespects explicit constraints64%
- passIdentifies material uncertainty76%
- passAvoids unsupported claims23%
- passProduces the required deliverable70%
- passChecks every criterion, region by region34%
- passFinds the Scotland breach88%
- passExplains the basket gap85%
- passCatches the duplicate rows86%
- partialMakes a clear call66%
- partialLimits the downside of being wrong91%
- failGets the base of every number right41%
- failJudges the launch against a baseline set now33%
Run
- Run
- #1
- API response time
- 44 s
- Submitted
- 29 Sept 2026