{
  "study": "Six digits against CBP's own rulings",
  "measured_on": "2026-09-17",
  "n": 98,
  "source": "U.S. Customs and Border Protection, Customs Rulings Online Search System (CROSS)",
  "frame": "CROSS ny, DATE_DESC, term=a (controlled non-selective)",
  "sample_dates": {
    "from": "2026-07-07",
    "to": "2026-08-14"
  },
  "collected": 130,
  "dropped_before_any_call": {
    "no_subject_match": 91,
    "not_one_code": 40,
    "code_too_short": 0,
    "no_description": 21,
    "leak": {
      "classification_word": 31,
      "hts_shaped_number": 16
    }
  },
  "exact_6_digit": {
    "n": 23,
    "pct": 23.5,
    "ci95": [
      16.2,
      32.8
    ]
  },
  "heading_4_digit": {
    "n": 38,
    "pct": 38.8
  },
  "chapter_2_digit": {
    "n": 58,
    "pct": 59.2
  },
  "misses": {
    "n": 75,
    "right_chapter_wrong_subheading": 35,
    "cbp_code_in_our_alternates": 8
  },
  "confidence": {
    "at_or_above_0_7": {
      "n": 66,
      "correct": 21
    },
    "below_0_7": {
      "n": 32,
      "correct": 2
    },
    "mean_when_correct": 0.817,
    "mean_when_incorrect": 0.618,
    "bands": [
      {
        "from": 0,
        "to": 0.3,
        "n": 7,
        "correct": 0,
        "pct": 0
      },
      {
        "from": 0.3,
        "to": 0.5,
        "n": 23,
        "correct": 2,
        "pct": 8.7
      },
      {
        "from": 0.5,
        "to": 0.7,
        "n": 2,
        "correct": 0,
        "pct": 0
      },
      {
        "from": 0.7,
        "to": 0.8,
        "n": 38,
        "correct": 5,
        "pct": 13.2
      },
      {
        "from": 0.8,
        "to": 0.9,
        "n": 17,
        "correct": 9,
        "pct": 52.9
      },
      {
        "from": 0.9,
        "to": 1,
        "n": 11,
        "correct": 7,
        "pct": 63.6
      }
    ],
    "refuse_below": [
      {
        "threshold": 0.5,
        "answers": 68,
        "correct": 21,
        "precision_pct": 30.9,
        "correct_answers_refused": 2
      },
      {
        "threshold": 0.7,
        "answers": 66,
        "correct": 21,
        "precision_pct": 31.8,
        "correct_answers_refused": 2
      },
      {
        "threshold": 0.75,
        "answers": 55,
        "correct": 21,
        "precision_pct": 38.2,
        "correct_answers_refused": 2
      },
      {
        "threshold": 0.8,
        "answers": 28,
        "correct": 16,
        "precision_pct": 57.1,
        "correct_answers_refused": 7
      },
      {
        "threshold": 0.85,
        "answers": 28,
        "correct": 16,
        "precision_pct": 57.1,
        "correct_answers_refused": 7
      },
      {
        "threshold": 0.9,
        "answers": 11,
        "correct": 7,
        "precision_pct": 63.6,
        "correct_answers_refused": 16
      }
    ]
  },
  "error_location": {
    "cbp_code_was_among_our_alternates": 8,
    "cbp_code_was_not_among_them": 67,
    "note": "An alternate carrying CBP's code shows the candidate set held the right answer and the choice stage rejected it. Its absence is consistent with the candidate set never containing it, which would make candidate generation rather than choice the dominant error, but this study does not capture the full candidate list and so does not prove it."
  },
  "by_cbp_chapter": [
    {
      "chapter": "85",
      "n": 15,
      "correct": 6
    },
    {
      "chapter": "84",
      "n": 12,
      "correct": 2
    },
    {
      "chapter": "87",
      "n": 12,
      "correct": 3
    },
    {
      "chapter": "95",
      "n": 8,
      "correct": 1
    },
    {
      "chapter": "68",
      "n": 7,
      "correct": 2
    },
    {
      "chapter": "30",
      "n": 6,
      "correct": 3
    },
    {
      "chapter": "39",
      "n": 6,
      "correct": 0
    },
    {
      "chapter": "42",
      "n": 5,
      "correct": 1
    },
    {
      "chapter": "83",
      "n": 5,
      "correct": 1
    },
    {
      "chapter": "76",
      "n": 4,
      "correct": 0
    },
    {
      "chapter": "90",
      "n": 4,
      "correct": 0
    },
    {
      "chapter": "16",
      "n": 3,
      "correct": 0
    },
    {
      "chapter": "29",
      "n": 2,
      "correct": 1
    },
    {
      "chapter": "63",
      "n": 2,
      "correct": 1
    },
    {
      "chapter": "20",
      "n": 1,
      "correct": 0
    },
    {
      "chapter": "21",
      "n": 1,
      "correct": 0
    },
    {
      "chapter": "40",
      "n": 1,
      "correct": 0
    },
    {
      "chapter": "49",
      "n": 1,
      "correct": 1
    },
    {
      "chapter": "64",
      "n": 1,
      "correct": 0
    },
    {
      "chapter": "73",
      "n": 1,
      "correct": 1
    },
    {
      "chapter": "06",
      "n": 1,
      "correct": 0
    }
  ],
  "attempted": 100,
  "answered": 98,
  "unanswered": {
    "n": 2,
    "statuses": {
      "503": 2
    },
    "rulings": [
      "N362772",
      "N362453"
    ]
  },
  "http_errors": 2
}