{
  "version": "ew-f6-v1",
  "frozenAt": "2026-10-13T08:16:04.369111+00:00",
  "scope": "F1-F6 acquisition and national feature bands only. No new collision screening or model fitting. F7-F9 unimplemented.",
  "planLibraryId": "libfile_6b9f2a2297708191a0322725eac33d2e",
  "sourceCommit": "a3ce9d591c77c0ff2ab6cc0f6ed2e8939075d79b",
  "master": "v1/master-geography.csv",
  "nationalLSOAs": 35672,
  "countryCounts": {
    "England": 33755,
    "Wales": 1917
  },
  "families": {
    "F2": [
      "school_density",
      "stop_density"
    ],
    "F3": [
      "claimant_rate",
      "claimant_change"
    ],
    "F4": [
      "road_gradient",
      "steep_road_share"
    ],
    "F5": [
      "heat_days_25",
      "heat_days_30",
      "heavy_rain",
      "rain_intensity",
      "snow_lying"
    ]
  },
  "priorRelease": "ew-v4",
  "priorFeatureLookup": "v3/full-feature-decile-lookup.csv.gz",
  "priorOutcomes": "Distinct motor-involved police-recorded injury collisions; all eligible zeros retained. F7 only.",
  "exposure": "Frozen Phase3/Phase4 physical and fitted mileage releases; offset log(miles/100000) for later F7.",
  "candidateRules": {
    "activity": {
      "bufferMetres": 100,
      "sensitivityBuffersMetres": [
        50,
        200
      ],
      "eligibleRoads": "OS non-fictitious public motor road functions; exclude Restricted Local Access Road and Secondary Access Road for primary activity denominator; archive mapping and road totals.",
      "school": "Open mainstream primary/secondary/all-through/special schools across both countries; pupil-referral and nursery-only settings excluded consistently; count unique establishments/sites under documented harmonisation.",
      "stops": "Active NaPTAN physical boarding/access sites; fixed eligible modes and site deduplication; no service-frequency claim.",
      "denominator": "Eligible road km in LSOA; source-complete no site = zero; no eligible road = unavailable.",
      "boundary": "Point sites assigned to their containing LSOA; distance to eligible roads within/outside boundary; one site counted at most once per LSOA."
    },
    "claimant": {
      "rate": "100 * annual mean claimants / matched residents aged 16-64; age universe must match.",
      "change": "Percentage-point difference between consecutive comparable annual mean rates.",
      "primaryReference": "2021 rate and 2021 minus 2020 change as lagged context for 2022 development; later lagged panels if accessible.",
      "geography": "Historical 2011 counts and denominators separately reconciled to LSOA2021; exact aggregations or validated allocation weights only.",
      "vintage": "Retrospective unless archived publication timing, denominator and geographic allocation are evidenced."
    },
    "terrain": {
      "spacingMetres": 50,
      "steepThresholdPct": 8,
      "sensitivityThresholdsPct": [
        5,
        10
      ],
      "gradient": "100 * absolute elevation difference / along-road metres; length weighted; unresolved bridge/tunnel structures flagged.",
      "resolution": "OS Terrain50 50m national terrain; proxy label retained unless road-surface validity independently established."
    },
    "weather": {
      "climateReference": "1991-2020; road-weighted national climate normals primary where exact definitions available.",
      "explanatoryYears": [
        2022,
        2023,
        2024,
        2025
      ],
      "heatDaysOperators": ">=",
      "heatDaysCelsius": [
        25,
        30
      ],
      "heavyRainDayMm": 10,
      "wetDayMm": 1,
      "rainIntensity": "Total rainfall on wet days / number of wet days; 0 wet days means unavailable intensity, not zero.",
      "snow": "Publisher count of days snow lying at supplied temporal resolution; source definition retained.",
      "coverage": "Complete source calendar per valid grid; >=99% road-metres covered per LSOA; no future observed weather in a pre-year score.",
      "access": "Use only authorised public or user-supplied files. Never bypass authentication or substitute strict >25 for >=25."
    }
  },
  "bandRules": {
    "cutpoints": "National nearest-rank deciles; bisect_left ensures equal values stay together.",
    "zeroBand": "Use Z0 plus positive deciles for school/stop density, steep share, heat and snow only if zero mass >=10%; otherwise ordinary D1-D10. Signed claimant change permits negative values.",
    "coverageGate": "At least 99% numeric master LSOAs overall and 95% within each country, region and urban/rural group; coverage and missingness extremes must also pass. Structural no-road values remain unavailable. Material geographically concentrated gaps withhold bands even when headline threshold passes.",
    "missingSensitivity": "Worst-case rank bounds placing all unknown values below or above observed values; at least 95% of observed assignments must change by at most one band. Report larger shifts and never treat missing as middle/zero.",
    "measurementGate": "Source definitions harmonised, denominators valid, location/road/terrain checks credible, complete-period checks passed. Failure keeps numeric diagnostic values but no national bands.",
    "unchangedPrior": "Every existing feature except the 11 originally deferred targets stays value/band/status identical; prior release files byte-identical.",
    "estimated": "Observed/estimated/inherited/unavailable recorded; no collision-derived estimation; estimated-only scenarios separate."
  },
  "laterValidation": {
    "developmentYears": [
      2022,
      2023
    ],
    "laterYears": "2024/2025 previously inspected diagnostics only; future complete uninspected period reserved.",
    "baseline": "Frozen Phase4 rich_poisson refit to same feature-eligible cohort.",
    "temporal": "2022 fit -> 2023 prediction",
    "spatial": "9 English regions plus Wales, leave-one-region-out",
    "primary": "categorical national bands",
    "fdr": "Fixed eleven-feature primary family, conservative unestimable p=1; combined 39-candidate sensitivity when complete.",
    "shortlist": "Original Phase5 gates retained; F7 only.",
    "newPredictiveClaims": false
  },
  "featureOutputContract": {
    "columns": [
      "lsoa",
      "feature",
      "value",
      "status"
    ],
    "units": "Feature-specific metadata; empty numeric value = unavailable.",
    "audits": "Each phase includes sources, acquiredAt, sha256, bytes, coverage, measurement-gate decisions, outstanding blockers and reproducible scripts."
  }
}