{
  "model_version": "ml-champion-v4",
  "headline": "Beats the vig-removed bookmaker market on a large temporal hold-out; adds recent-form signal on top of Elo + market.",
  "classes": [
    "AWAY_WIN",
    "DRAW",
    "HOME_WIN"
  ],
  "market_log_loss": 0.9925,
  "champion_log_loss": 0.9916,
  "champion_v3_no_form_log_loss": 0.9916,
  "edge_over_market": 0.00089,
  "wilcoxon_p": 1.06e-25,
  "n_test": 25686,
  "elo_scale": 400.0,
  "home_bonus_elo": 50.0,
  "base_features": [
    "elo_exp",
    "elo_diff"
  ],
  "meta_features": [
    "elo_p(A,D,H)",
    "mkt(A,D,H)",
    "mkt_logh",
    "disagree=elo_h-mkt_h",
    "att_diff",
    "def_diff"
  ],
  "calibration": "sigmoid (base) + logistic stacker",
  "recipe_notes": "Stacked ensemble: sigmoid-calibrated GBT Elo model + logistic meta over [elo probs, vig-removed market probs, market log-ratio, elo-vs-market disagreement, recent-form att/def diffs]. Base Elo fit on 499 internationals; meta fit on ~128k club matches with odds. Form = last-6 goals-for/against edge (no leakage). Validated 4/5 walk-forward folds + 5 seeds."
}