{
  "version": "0.5.0",
  "date": "2026-10-20",
  "status": "Local analysis specification; no external preregistration. Public-data analysis is retrospective.",
  "primary_dataset": "PanTHERIA WR05 August 2008 from original Wiley/Figshare archive",
  "mass_column": "5-2_BasalMetRateMass_g",
  "response_column": "18-1_BasalMetRate_mLO2hr",
  "oxygen_conversion_J_per_mL": 20.1,
  "models": [
    "M0 single line",
    "M1 fixed continuous hinge at 10 kg",
    "M2 quadratic in log mass",
    "M1_20kg sensitivity fixed at 20 kg"
  ],
  "response": "log10 watts",
  "predictor": "log10 kg",
  "seed": 20261020,
  "primary_split": "Families grouped; sorted by median log mass into ten equal-count strata; within each stratum assign first floor(0.3*n+0.5), minimum one when n>=2, by SHA256(seed:family) to test; others train. No family crossing.",
  "sensitivity_split": "Species sorted into ten mass strata; SHA256(seed:binomial), same allocation rule.",
  "resampling": "2000 train-family and test-family bootstrap samples; refit each model; fixed holdout assignment; percentile 95% intervals. Family grouping is not a phylogenetic covariance model.",
  "aicc": "Training log-response likelihood only; parameters include residual variance. Descriptive iid approximation, not a cluster-corrected decision statistic. No AICc on held-out observations.",
  "coverage_gate": {
    "above_10kg_total": 25,
    "above_10kg_train": 15,
    "above_10kg_test": 8,
    "above_10kg_families": 5
  },
  "hinge_vs_single_rule": "Requires coverage, >5% test RMSE reduction, positive lower 95% bound for M0-M1 paired test MSE difference, and positive lower 95% bound for slope change. A retrospective descriptive screen, not confirmatory evidence.",
  "quadratic": "Compare paired test errors directly; a hinge advantage over M0 alone does not distinguish hinge from smooth curvature.",
  "sensitivity": [
    "20 kg fixed hinge",
    "species-stratified split",
    "five-fold family CV",
    "additive-error nonlinear least squares in watts"
  ],
  "open_limits": [
    "No tree-based PGLS",
    "Temperature and source-method confounding",
    "Unknown within-species measurement uncertainty",
    "Cross-compilation overlap audit required before claiming replication"
  ]
}