{"version":"ew-v2","status":"E1–E3 incremental expansion; E4–E7 deferred; E8 final expansion freeze pending","frozenAt":"2026-10-12","masterCount":35672,"countries":{"England":33755,"Wales":1917},"masterSha256":"3c6cd1f08810ad1c3f87f814a82f967c00f32e2943b2ebd82789589d6bd68e6b","priorVersion":"ew-v1","baselinePreservation":"ew-v1 files, values and bands are immutable. Old explorer series are referenced from ew-v1; no-car is reused.","inventory":{"originalCalculated":22,"originalDeferred":16,"expansionCandidates":23,"newCalculated":11,"newDeferred":12,"totalCandidates":61,"totalCalculated":33,"totalDeferred":28},"duplicationDecisions":["No-car already in ew-v1; not added again","E2 walk/cycle participation and E3 accessibility reused in E6; not flow estimates","NaPTAN stop_density remains the existing deferred candidate; separate from DfT connectivity","Heat thresholds differ from existing frost/snow/rain candidates","Bankruptcy is nested in insolvency; multi-car/3+ and mode shares overlap; joint selection required"],"ranking":"Combined England and Wales, one LSOA one weight. Eligibility depends only on source coverage and applicability, never collisions, claims or mileage quality.","ties":"Empirical inverse CDF ceil(n*p), equality in lower band; ties together; unequal and empty bands retained.","zeros":"Observed zero is numeric. New E2/E3 features use D1–D10; zeros stay tied. Future sparse features may use a registered Z + positive decile scheme before outcome analysis.","missingness":"All master rows retained. Valid zero, missing denominator, no reporting, not applicable and deferred are distinct states. No imputation in E1–E3.","geography":"Exact LSOA2021 inputs; no crosswalk in E2/E3. Future historical counts and denominators must be crosswalked before rates/bands, never average deciles.","dates":"Census 2021 is pandemic baseline. DfT workbook reference Q4 2024, mixed vintages, published 2025-09-29. Frozen bands created 2026-10-12. No certified historical as-of score.","futureAssignments":"Later values may be assigned to these saved cutoffs without refitting. Rebaselining requires a new version and transition table.","exposureAudit":{"script":"scripts/build-frost-mileage.py","sha256":"632e28d933d540984ba59a07baa5216348eb4359797d0e47e54db3d09e327dfd","inputs":["region","roadClass","function","logDensity","urbanFraction","degree"],"newE2E3FeaturesUsed":false,"nationwideAudit":"pending","sensitivity":"Before testing accident effects, audit exposure inputs and compare independently counted traffic subsets and alternative exposure models."},"deferredLicenceGate":"E4–E7 sources are identified only; exact source edition, release, checksum and reuse terms remain explicitly unacquired. No unverified data ingested.","outcomesUsed":false,"claimsValidation":false}