{
  "evidence_edition": "bathing-experimental-1-20260924",
  "prebuild_attestation_sha256": "89338c8313e87bb7c6265826ade51c23226aea227123cf1ef9d3984f752102c7",
  "source": {
    "attribution": "Source: Environment Agency bathing-water classifications. Contains public sector information licensed under the Open Government Licence v3.0. CoryVu derived analysis; no endorsement implied.",
    "dataset": "Annual bathing water classifications, England archive",
    "document_hashes": {
      "bathing-2025-table.html": "c89f36eca79a584543248f09141a08c8f50dc0fc29170618746d95fabae2c654",
      "bathing-gap.html": "1fc5afd7ff7db58f57805be55a5ffdba710ea755188081f934a71f126d03afb8",
      "bathing-home.html": "3efdd031c7b2cf23c3f362ce1960d13beec8f8354d6682860a5d6b7329342e62",
      "bathing-licence.html": "99b450d5e9d761850da9b68058f01b8dc5ba231cda3c579de5c0e143dfc8d4c2",
      "bathing-statistics.html": "49599dede7d95ae0dd9146dfe441c0af3ea9ec689ee5fe589baf887acccfcb8a",
      "ogl3.html": "f5b2b9f2af63647cde889fa6c3508f5705925295b74912c68caa28dd37e64aa5"
    },
    "geography": "England",
    "licence": "OGL-3.0",
    "limits": [
      "Archive-returned site IDs, not proof of every historically designated site",
      "Annual labels are not instantaneous water quality or swimming safety",
      "No classification in 2020; adjacent-year comparisons do not bridge it",
      "Multi-year sampling windows overlap; historical pairs are not independent trials",
      "2021-2023 used four sample years drawn from five calendar years",
      "No prediction or current-safety recommendation",
      "Closed/non-ranked and missing records excluded explicitly"
    ],
    "method_sha256": "d7cba396c2eb4dc2b51e2596e7798beef4914a296860aebcd4f11c989a61f92d",
    "method_version": "bathing-experimental-1",
    "publisher": "Environment Agency",
    "raw_hashes": {
      "raw.zip": "eb6659d33f548cf24462b424c7afb49db74891032c4bb48eaca96b6c42346444"
    },
    "units": "published annual classification labels",
    "version": "archive captured 24 September 2026; official actual classes 2015-2025"
  },
  "method": "Question: Which changes between the four official annual English bathing-water classes occurred in adjacent calendar years 2015-2025, including whether Excellent changed directly to Poor? Population: union of site IDs appearing in the captured classification archive over 2015-2025; enumerate each site x 2015..2025 and each site x start-year 2015..2024. Include a pair only when both adjacent years have one unique valid official class Excellent/Good/Sufficient/Poor. Missing or unclassified years are explicit exclusions; never bridge gaps (including 2020). Reject conflicting duplicate site/year observations and unknown codes. Historical published classifications, often based on overlapping multi-year samples, are the observed object: no claim of sudden physical change, independent trials, swimming safety or current conditions. Pre-2015 projected classifications excluded. Derive full transition matrix, stable/improved/worsened counts, per-year summaries and all direct Excellent-to-Poor pairs; preserve source line identities. Do not adjust for interesting results.\n",
  "verified_result_sha256": "613d3cbecc81308470682fa1f73d4bbe176d202e2dbdb1f13e225afe9662f2ff",
  "downloads": {
    "annual.csv": "ff2341bf9ad6ec97375c944aebadc45c98f4aa3d415e69892e0873ca21887bf9",
    "data-dictionary.json": "a2aa1bd22a71b7eba473e0a7510d719481b485375c178b6b701f78fe738daf77",
    "excluded.csv": "b522a9673fcaf0703e538ae6e1ce258a5882b9b2556b3c639ac2082b59c98916",
    "observations.csv": "2b61e282b6ccd69317cbdab2df25566bebb7e21c1b6b1a94a7a3397b4c42d04b",
    "rows.csv": "a836052decaea3c3461b4d3f9c6406f147b21ee4f98267759bd6be66ddb767dc"
  }
}