{
  "task": 1946,
  "analysis": "language-stratified mirror recomputation (free-analysis follow-up)",
  "inputs": {
    "sae_csv": "eval_results/issue_1946/percontext_summary_L19_ridge_sae.csv",
    "dense_csv": "eval_results/issue_1738/percontext_summary_L19_ridge.csv",
    "bare_csv": "eval_results/issue_1738/bare_query/percontext_summary_L19_ridge.csv"
  },
  "n_joined": 9941,
  "n_en": 5870,
  "n_non_en": 4071,
  "n_language_nan_in_rest": 16,
  "stratum_convention": "en = (language == 'en'); NaN-language rows fall in rest, matching issue1738_characterize._contrast_masks",
  "per_space": {
    "sae": {
      "en": {
        "n": 5870,
        "mean_nerr": {
          "prefix": 0.700274421294719,
          "bare": 0.61201917120954,
          "context": 0.44817550051107324
        },
        "mean_prefix_minus_bare": 0.08825525008517887
      },
      "rest": {
        "n": 4071,
        "mean_nerr": {
          "prefix": 0.6027260390567427,
          "bare": 0.4611974893146647,
          "context": 0.3593682888725129
        },
        "mean_prefix_minus_bare": 0.14152854974207812
      },
      "delta_en_vs_rest": {
        "prefix": 0.09754838223797624,
        "bare": 0.15082168189487527,
        "context": 0.08880721163856037
      },
      "M_en": -0.05327329965689903
    },
    "dense": {
      "en": {
        "n": 5870,
        "mean_nerr": {
          "prefix": 0.6467158536626917,
          "bare": 0.5056621260647359,
          "context": 0.3438519584327087
        },
        "mean_prefix_minus_bare": 0.1410537275979557
      },
      "rest": {
        "n": 4071,
        "mean_nerr": {
          "prefix": 0.5673717720461802,
          "bare": 0.43794076295750434,
          "context": 0.31146861508228935
        },
        "mean_prefix_minus_bare": 0.129431009088676
      },
      "delta_en_vs_rest": {
        "prefix": 0.07934408161651152,
        "bare": 0.06772136310723159,
        "context": 0.03238334335041937
      },
      "M_en": 0.011622718509279928
    }
  },
  "decomposition": {
    "delta_prefix_en": {
      "dense": 0.07934408161651152,
      "sae": 0.09754838223797624,
      "change": 0.01820430062146472
    },
    "delta_bare_en": {
      "dense": 0.06772136310723159,
      "sae": 0.15082168189487527,
      "change": 0.08310031878764368
    },
    "M_en": {
      "dense": 0.011622718509279928,
      "sae": -0.05327329965689903,
      "change": -0.06489601816617896
    },
    "bare_share_of_change": 0.8203013769002132,
    "localization_rule": "yes if |bare component| >= 75% of summed |components|, no if <= 25%, else mixed"
  },
  "bootstrap": {
    "n_boot": 10000,
    "seed": 1946,
    "resampling": "context-level (rows resampled with replacement; shared indices across spaces => paired difference)",
    "M_en_sae": {
      "mean": -0.05331362415972351,
      "ci95": [
        -0.06780495126920347,
        -0.038804105970349834
      ],
      "frac_draws_below_zero": 1.0,
      "frac_draws_above_zero": 0.0
    },
    "M_en_dense": {
      "mean": 0.011572151382393432,
      "ci95": [
        -0.0021987287371751187,
        0.025009980238594402
      ],
      "frac_draws_below_zero": 0.05,
      "frac_draws_above_zero": 0.95
    },
    "M_en_sae_minus_dense": {
      "mean": -0.06488577554211693,
      "ci95": [
        -0.07528985372861123,
        -0.05443968281690106
      ],
      "frac_draws_below_zero": 1.0,
      "frac_draws_above_zero": 0.0
    }
  },
  "verdict": "flip localized to bare-arm English magnitude: yes (bare component +0.0831 = 82% of the dense->SAE M_en change vs prefix component +0.0182; SAE M_en -0.0533 is distinguishable from zero and distinguishable from the dense M_en +0.0116 at 95% context-level bootstrap CIs)",
  "metadata": {
    "git_commit": "ff31e2c180529ce9e71f8e863778fcd4f1801e1e",
    "timestamp_utc": "2026-08-01T04:00:01.236770+00:00",
    "numpy": "2.2.6",
    "pandas": "2.3.3",
    "python": "3.11.15",
    "script": "scripts/issue1946_lang_stratified.py"
  }
}