{
  "synthetic": false,
  "created_utc": "2026-10-23T10:36:58.746153+00:00",
  "model": "original XGBoost plus learned chronological logistic stack and selected score blend",
  "base_training_years": [
    2015,
    2016,
    2017,
    2018,
    2019,
    2020,
    2021
  ],
  "meta_selection_training_years": [
    2019,
    2020
  ],
  "validation_years": [
    2021,
    2022
  ],
  "meta_final_training_years": [
    2019,
    2020,
    2021
  ],
  "calibration_year": 2022,
  "selection_max_year": 2022,
  "selection_rule": "C selected on 2021; blend maximizes minimum relative recall gain across 2021 at precision>=0.10 and 2022 at original operating precision; AP must improve in both years",
  "threshold_rule": "max 2022 weighted recall with precision no lower than original XGBoost 2022 operating precision",
  "history_lag_days": 2,
  "history_windows": [
    [
      7,
      3
    ],
    [
      7,
      11
    ],
    [
      30,
      3
    ],
    [
      30,
      11
    ],
    [
      90,
      11
    ],
    [
      365,
      11
    ]
  ],
  "meta_C_candidates": [
    0.01,
    0.1,
    1
  ],
  "meta_blend_weights": [
    1,
    0.75,
    0.5,
    0.25
  ],
  "test_previously_reported": true,
  "test_used_for_selection": false,
  "transport": "float16 rounding before calibration operating-point evaluation and all final metrics",
  "previous_failed_experiments": [
    "model_upgrade_v3",
    "model_upgrade_v4"
  ],
  "lineage": "OOF first-stage scores were produced by models fitted on years strictly earlier than each OOF year"
}