{
  "question": "Is the phase-share gradient mechanical, driven by longer games at higher ratings?",
  "normalisations": {
    "relative_position": "decisive ply / total plies — flat across bands would mean pure artefact",
    "conditional_endgame_share": "among games reaching ply 61, share decided at ply 61+ — removes truncation entirely"
  },
  "results": {
    "700-899": {
      "games_decided": 1526,
      "median_game_length_plies": 49,
      "relative_position": {
        "p25": 0.483,
        "median": 0.781,
        "p75": 0.978
      },
      "reached_endgame_ply61": 532,
      "share_of_games_reaching_endgame": 0.349,
      "conditional_endgame_share": 0.453,
      "conditional_endgame_ci95": [
        0.411,
        0.495
      ]
    },
    "900-1099": {
      "games_decided": 1577,
      "median_game_length_plies": 54,
      "relative_position": {
        "p25": 0.53,
        "median": 0.818,
        "p75": 0.974
      },
      "reached_endgame_ply61": 619,
      "share_of_games_reaching_endgame": 0.393,
      "conditional_endgame_share": 0.459,
      "conditional_endgame_ci95": [
        0.42,
        0.498
      ]
    },
    "1100-1299": {
      "games_decided": 1639,
      "median_game_length_plies": 55,
      "relative_position": {
        "p25": 0.545,
        "median": 0.816,
        "p75": 0.972
      },
      "reached_endgame_ply61": 688,
      "share_of_games_reaching_endgame": 0.42,
      "conditional_endgame_share": 0.49,
      "conditional_endgame_ci95": [
        0.453,
        0.527
      ]
    },
    "1300-1499": {
      "games_decided": 1670,
      "median_game_length_plies": 59,
      "relative_position": {
        "p25": 0.574,
        "median": 0.816,
        "p75": 0.974
      },
      "reached_endgame_ply61": 800,
      "share_of_games_reaching_endgame": 0.479,
      "conditional_endgame_share": 0.468,
      "conditional_endgame_ci95": [
        0.433,
        0.502
      ]
    },
    "1500-1799": {
      "games_decided": 1660,
      "median_game_length_plies": 62,
      "relative_position": {
        "p25": 0.603,
        "median": 0.826,
        "p75": 0.969
      },
      "reached_endgame_ply61": 882,
      "share_of_games_reaching_endgame": 0.531,
      "conditional_endgame_share": 0.528,
      "conditional_endgame_ci95": [
        0.495,
        0.561
      ]
    },
    "1800-2000": {
      "games_decided": 1690,
      "median_game_length_plies": 66,
      "relative_position": {
        "p25": 0.597,
        "median": 0.831,
        "p75": 0.966
      },
      "reached_endgame_ply61": 998,
      "share_of_games_reaching_endgame": 0.591,
      "conditional_endgame_share": 0.533,
      "conditional_endgame_ci95": [
        0.502,
        0.564
      ]
    }
  }
}