{
 "artifact": "NCM_HISTORICAL_RECONCILIATION_V1",
 "firebird_writes": 0,
 "items_with_ncm": 4668,
 "items_joined_to_product": 2917,
 "orphan_items_no_product": 1751,
 "mismatches_total": 1676,
 "mismatches_in_initial_sample_5000": 1671,
 "classification": {
  "BAD_JOIN": 1661,
  "UNKNOWN": 11,
  "TRUE_HISTORICAL_DIFFERENCE": 4
 },
 "reasons": {
  "BAD_JOIN|SYSTEMIC_WINDOW_2022-12": 1565,
  "BAD_JOIN|SYSTEMIC_WINDOW_2024-01": 40,
  "BAD_JOIN|SYSTEMIC_WINDOW_2025-12": 32,
  "BAD_JOIN|ALT_PRODUCT_WITH_SAME_NCM_AND_PRICE": 24,
  "UNKNOWN|ITEM_NCM_NOT_VALID_IN_NCM_DATASET": 11,
  "TRUE_HISTORICAL_DIFFERENCE|ISOLATED_DIFFERENCE_PRODUCT_OTHERWISE_CONSISTENT_UNPROVEN_CAUSE": 4
 },
 "systemic_bad_join_windows": {
  "2022-12": {
   "matches": 47,
   "mismatches": 1565
  },
  "2024-01": {
   "matches": 28,
   "mismatches": 40
  },
  "2025-12": {
   "matches": 20,
   "mismatches": 32
  }
 },
 "window_rule": "month with >= 50% NCM disagreement is treated as a systemic bad-join window",
 "mismatches_by_month": {
  "2022-12": 1565,
  "2023-11": 4,
  "2024-01": 40,
  "2024-02": 5,
  "2024-03": 26,
  "2025-05": 2,
  "2025-12": 32,
  "2026-03": 2
 },
 "examples": {
  "BAD_JOIN": [
   {
    "nfce_item_id": 30641,
    "product": "000280",
    "product_desc": "CAJU M/ JARRA",
    "product_ncm": "20099000",
    "item_ncm": "19022000",
    "date": "2022-12-01",
    "reason": "SYSTEMIC_WINDOW_2022-12"
   },
   {
    "nfce_item_id": 30642,
    "product": "000280",
    "product_desc": "CAJU M/ JARRA",
    "product_ncm": "20099000",
    "item_ncm": "19022000",
    "date": "2022-12-01",
    "reason": "SYSTEMIC_WINDOW_2022-12"
   },
   {
    "nfce_item_id": 30643,
    "product": "000058",
    "product_desc": "PAO DE ALHO",
    "product_ncm": "19059010",
    "item_ncm": "22030000",
    "date": "2022-12-01",
    "reason": "SYSTEMIC_WINDOW_2022-12"
   },
   {
    "nfce_item_id": 30644,
    "product": "000058",
    "product_desc": "PAO DE ALHO",
    "product_ncm": "19059010",
    "item_ncm": "22030000",
    "date": "2022-12-01",
    "reason": "SYSTEMIC_WINDOW_2022-12"
   }
  ],
  "UNKNOWN": [
   {
    "nfce_item_id": 34122,
    "product": "000792",
    "product_desc": "MOUSE GTI",
    "product_ncm": "84716053",
    "item_ncm": "00000000",
    "date": "2023-11-29",
    "reason": "ITEM_NCM_NOT_VALID_IN_NCM_DATASET"
   },
   {
    "nfce_item_id": 34123,
    "product": "000792",
    "product_desc": "MOUSE GTI",
    "product_ncm": "84716053",
    "item_ncm": "00000000",
    "date": "2023-11-29",
    "reason": "ITEM_NCM_NOT_VALID_IN_NCM_DATASET"
   },
   {
    "nfce_item_id": 34130,
    "product": "000783",
    "product_desc": "LIXEIRA",
    "product_ncm": "39229000",
    "item_ncm": "11111111",
    "date": "2023-11-29",
    "reason": "ITEM_NCM_NOT_VALID_IN_NCM_DATASET"
   },
   {
    "nfce_item_id": 34131,
    "product": "000783",
    "product_desc": "LIXEIRA",
    "product_ncm": "39229000",
    "item_ncm": "11111111",
    "date": "2023-11-29",
    "reason": "ITEM_NCM_NOT_VALID_IN_NCM_DATASET"
   }
  ],
  "TRUE_HISTORICAL_DIFFERENCE": [
   {
    "nfce_item_id": 35574,
    "product": "000700",
    "product_desc": "TESTE ERRO NA EMISSÃO DA NFCE (136)",
    "product_ncm": "62046200",
    "item_ncm": "08043000",
    "date": "2025-05-15",
    "reason": "ISOLATED_DIFFERENCE_PRODUCT_OTHERWISE_CONSISTENT_UNPROVEN_CAUSE"
   },
   {
    "nfce_item_id": 35576,
    "product": "000700",
    "product_desc": "TESTE ERRO NA EMISSÃO DA NFCE (136)",
    "product_ncm": "62046200",
    "item_ncm": "08043000",
    "date": "2025-05-15",
    "reason": "ISOLATED_DIFFERENCE_PRODUCT_OTHERWISE_CONSISTENT_UNPROVEN_CAUSE"
   },
   {
    "nfce_item_id": 35684,
    "product": "000700",
    "product_desc": "TESTE ERRO NA EMISSÃO DA NFCE (136)",
    "product_ncm": "62046200",
    "item_ncm": "08043000",
    "date": "2026-03-17",
    "reason": "ISOLATED_DIFFERENCE_PRODUCT_OTHERWISE_CONSISTENT_UNPROVEN_CAUSE"
   },
   {
    "nfce_item_id": 35686,
    "product": "000700",
    "product_desc": "TESTE ERRO NA EMISSÃO DA NFCE (136)",
    "product_ncm": "62046200",
    "item_ncm": "08043000",
    "date": "2026-03-17",
    "reason": "ISOLATED_DIFFERENCE_PRODUCT_OTHERWISE_CONSISTENT_UNPROVEN_CAUSE"
   }
  ]
 },
 "technical_bugs_found": {
  "normalization": 0,
  "note": "0 => no code bug; the mismatches are data-identity problems (CODPRODUTO does not reliably identify the product in 2022-12 and a few other windows)."
 },
 "trusted_corpus": {
  "definition": "NFC-e item with NCM present, product exists, item NCM == product NCM (identity proof), 8-digit NCM, month not a systemic window",
  "TRUSTED_HISTORICAL_ITEMS": 1146,
  "excluded_matches_in_windows": 95,
  "items_without_ncm_not_trusted": 30278
 }
}