{
  "primary_comparison": "Matched original-architecture GRASP control, A1, A2; training replicate 0; three shared outer splits.",
  "matched_endpoint_split_triplets": 69,
  "individual_prediction_cells_verified": 207,
  "model_mean_endpoint_mae": {
    "control": 0.3702320498982857,
    "a1": 0.3685879578170505,
    "a2": 0.3662318774785543
  },
  "model_split_macro_population_sd": {
    "control": 0.004206375431646905,
    "a1": 0.0010903069555724331,
    "a2": 0.002152111407523036
  },
  "lowest_mean_endpoint_counts": {
    "a1": 10,
    "control": 8,
    "a2": 5
  },
  "contrasts": [
    {
      "baseline": "control",
      "changed": "a1",
      "mean_mae_difference": -0.001644092081235165,
      "relative_macro_mae_reduction_pct": 0.4440707069220114,
      "endpoint_bootstrap_lower95": -0.011490278989452225,
      "endpoint_bootstrap_upper95": 0.008019370245648885,
      "changed_lower_endpoints": 11,
      "changed_higher_endpoints": 12,
      "changed_lower_split_cells": 36
    },
    {
      "baseline": "control",
      "changed": "a2",
      "mean_mae_difference": -0.00400017241973136,
      "relative_macro_mae_reduction_pct": 1.0804500639073136,
      "endpoint_bootstrap_lower95": -0.012635722835392695,
      "endpoint_bootstrap_upper95": 0.004425803942156549,
      "changed_lower_endpoints": 14,
      "changed_higher_endpoints": 9,
      "changed_lower_split_cells": 37
    },
    {
      "baseline": "a1",
      "changed": "a2",
      "mean_mae_difference": -0.002356080338496194,
      "relative_macro_mae_reduction_pct": 0.6392179365951124,
      "endpoint_bootstrap_lower95": -0.010505056285555462,
      "endpoint_bootstrap_upper95": 0.004859561931627686,
      "changed_lower_endpoints": 8,
      "changed_higher_endpoints": 15,
      "changed_lower_split_cells": 38
    }
  ],
  "repeat_context": {
    "control": 0.3652608053129453,
    "a1": 0.36943776142909285
  },
  "historical_released_grasp_macro_mae": 0.374183478126786,
  "bootstrap": {
    "draws": 100000,
    "seed": 20261024,
    "unit": "endpoint mean across the three fixed splits",
    "interval": "95% percentile, exploratory; no multiplicity correction"
  },
  "checks": "Passed: cohort hashes and row counts, ordered test targets, split IDs, seeds, run configs, software versions, Step2 data/recipe, initialized heads; all primary MAEs recomputed.",
  "limitations": [
    "One pretraining seed per architecture and one matched downstream replicate for A2.",
    "A2 has fewer downstream replicates than the completed control/A1 repeated evaluation.",
    "Fixed test molecules recur across outer splits; they are not three independent data collections.",
    "Different endpoint scales make the macro MAE a collection-specific score, not a scale-free effect.",
    "Endpoint bootstrap omits pretraining-seed variance and does not establish architectural causation; endpoints share data sources.",
    "Chemistry-enabled runner hash differs intentionally from control/A1; scientific settings and cohorts were compared explicitly.",
    "A2 TDC and A3 downstream results are not covered. No chemical mechanism for individual gains or losses is inferred."
  ]
}