{
  "computed_at": "2026-09-12T15:42:16+00:00",
  "sample": {
    "mock_attempts": 439,
    "mock_users": 140,
    "answered_items": 9689,
    "exercise_attempts": 60804,
    "srs_cards": 52491,
    "srs_words_qualifying": 203
  },
  "section_by_level": [
    {
      "level": 1,
      "section": "listening",
      "answered": 1704,
      "wrong_pct": 15.3
    },
    {
      "level": 1,
      "section": "reading",
      "answered": 2604,
      "wrong_pct": 18.7
    },
    {
      "level": 2,
      "section": "listening",
      "answered": 797,
      "wrong_pct": 11.7
    },
    {
      "level": 2,
      "section": "reading",
      "answered": 1342,
      "wrong_pct": 22.1
    },
    {
      "level": 3,
      "section": "listening",
      "answered": 1086,
      "wrong_pct": 16.9
    },
    {
      "level": 3,
      "section": "reading",
      "answered": 379,
      "wrong_pct": 17.9
    },
    {
      "level": 4,
      "section": "listening",
      "answered": 422,
      "wrong_pct": 12.8
    },
    {
      "level": 4,
      "section": "reading",
      "answered": 555,
      "wrong_pct": 19.8
    },
    {
      "level": 5,
      "section": "listening",
      "answered": 497,
      "wrong_pct": 19.1
    },
    {
      "level": 5,
      "section": "reading",
      "answered": 303,
      "wrong_pct": 28.7
    }
  ],
  "parts": [
    {
      "level": 5,
      "section": "reading",
      "part": 1,
      "format_zh": "选词填空",
      "format_id": "pilih kata untuk isi kalimat",
      "format_en": "choose the word for the blank",
      "answered": 115,
      "wrong_pct": 38.3
    },
    {
      "level": 4,
      "section": "reading",
      "part": 2,
      "format_zh": "排列顺序",
      "format_id": "urutkan kalimat",
      "format_en": "order the sentences",
      "answered": 140,
      "wrong_pct": 32.9
    },
    {
      "level": 2,
      "section": "reading",
      "part": 2,
      "format_zh": "选词填空",
      "format_id": "isi kalimat dengan kata dari kotak",
      "format_en": "fill the blank from a word bank",
      "answered": 264,
      "wrong_pct": 31.1
    },
    {
      "level": 1,
      "section": "reading",
      "part": 3,
      "format_zh": "问答匹配",
      "format_id": "jodohkan tanya–jawab",
      "format_en": "match question to answer",
      "answered": 640,
      "wrong_pct": 29.1
    },
    {
      "level": 5,
      "section": "reading",
      "part": 2,
      "format_zh": "阅读理解",
      "format_id": "pemahaman bacaan pendek",
      "format_en": "short reading comprehension",
      "answered": 73,
      "wrong_pct": 28.8
    },
    {
      "level": 3,
      "section": "reading",
      "part": 2,
      "format_zh": "选词填空",
      "format_id": "isi kalimat dengan kata dari kotak",
      "format_en": "fill the blank from a word bank",
      "answered": 130,
      "wrong_pct": 25.4
    },
    {
      "level": 1,
      "section": "reading",
      "part": 4,
      "format_zh": "选词填空",
      "format_id": "isi kalimat dengan kata dari kotak",
      "format_en": "fill the blank from a word bank",
      "answered": 635,
      "wrong_pct": 24.4
    },
    {
      "level": 2,
      "section": "reading",
      "part": 4,
      "format_zh": "问答匹配",
      "format_id": "jodohkan tanya–jawab",
      "format_en": "match question to answer",
      "answered": 528,
      "wrong_pct": 24.2
    },
    {
      "level": 5,
      "section": "listening",
      "part": 2,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog/monolog panjang",
      "format_en": "long passage, pick the answer",
      "answered": 241,
      "wrong_pct": 22.4
    },
    {
      "level": 3,
      "section": "listening",
      "part": 2,
      "format_zh": "判断对错",
      "format_id": "benar / salah pernyataan",
      "format_en": "true/false statement",
      "answered": 283,
      "wrong_pct": 21.2
    },
    {
      "level": 1,
      "section": "listening",
      "part": 4,
      "format_zh": "选答案",
      "format_id": "pilih jawaban",
      "format_en": "pick the answer",
      "answered": 401,
      "wrong_pct": 19.2
    },
    {
      "level": 5,
      "section": "reading",
      "part": 3,
      "format_zh": "阅读理解",
      "format_id": "pemahaman bacaan panjang",
      "format_en": "long reading comprehension",
      "answered": 115,
      "wrong_pct": 19.1
    },
    {
      "level": 2,
      "section": "reading",
      "part": 1,
      "format_zh": "配图",
      "format_id": "jodohkan kalimat–gambar",
      "format_en": "match sentence to picture",
      "answered": 280,
      "wrong_pct": 18.6
    },
    {
      "level": 4,
      "section": "reading",
      "part": 3,
      "format_zh": "阅读理解",
      "format_id": "pemahaman bacaan",
      "format_en": "reading comprehension",
      "answered": 270,
      "wrong_pct": 18.5
    },
    {
      "level": 1,
      "section": "listening",
      "part": 2,
      "format_zh": "选图",
      "format_id": "pilih gambar",
      "format_en": "pick the picture",
      "answered": 437,
      "wrong_pct": 17.2
    },
    {
      "level": 3,
      "section": "listening",
      "part": 4,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog panjang",
      "format_en": "long dialogue, pick the answer",
      "answered": 228,
      "wrong_pct": 17.1
    },
    {
      "level": 5,
      "section": "listening",
      "part": 1,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog pendek",
      "format_en": "short dialogue, pick the answer",
      "answered": 256,
      "wrong_pct": 16.0
    },
    {
      "level": 3,
      "section": "listening",
      "part": 1,
      "format_zh": "配图",
      "format_id": "jodohkan dialog–gambar",
      "format_en": "match dialogue to picture",
      "answered": 311,
      "wrong_pct": 15.8
    },
    {
      "level": 4,
      "section": "listening",
      "part": 3,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog/monolog panjang",
      "format_en": "long passage, pick the answer",
      "answered": 170,
      "wrong_pct": 15.3
    },
    {
      "level": 1,
      "section": "listening",
      "part": 1,
      "format_zh": "判断对错",
      "format_id": "benar / salah dari gambar",
      "format_en": "true/false from picture",
      "answered": 448,
      "wrong_pct": 14.5
    },
    {
      "level": 3,
      "section": "reading",
      "part": 3,
      "format_zh": "阅读理解",
      "format_id": "pemahaman bacaan pendek",
      "format_en": "short reading comprehension",
      "answered": 119,
      "wrong_pct": 14.3
    },
    {
      "level": 3,
      "section": "reading",
      "part": 1,
      "format_zh": "问答匹配",
      "format_id": "jodohkan tanya–jawab",
      "format_en": "match question to answer",
      "answered": 130,
      "wrong_pct": 13.8
    },
    {
      "level": 3,
      "section": "listening",
      "part": 3,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog pendek",
      "format_en": "short dialogue, pick the answer",
      "answered": 264,
      "wrong_pct": 13.6
    },
    {
      "level": 4,
      "section": "listening",
      "part": 1,
      "format_zh": "判断对错",
      "format_id": "benar / salah pernyataan",
      "format_en": "true/false statement",
      "answered": 111,
      "wrong_pct": 13.5
    },
    {
      "level": 2,
      "section": "listening",
      "part": 2,
      "format_zh": "配图",
      "format_id": "jodohkan dialog–gambar",
      "format_en": "match dialogue to picture",
      "answered": 235,
      "wrong_pct": 13.2
    },
    {
      "level": 2,
      "section": "reading",
      "part": 3,
      "format_zh": "判断对错",
      "format_id": "benar / salah pernyataan",
      "format_en": "true/false statement",
      "answered": 270,
      "wrong_pct": 13.0
    },
    {
      "level": 2,
      "section": "listening",
      "part": 3,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog pendek",
      "format_en": "short dialogue, pick the answer",
      "answered": 219,
      "wrong_pct": 11.9
    },
    {
      "level": 1,
      "section": "reading",
      "part": 2,
      "format_zh": "配图",
      "format_id": "jodohkan kalimat–gambar",
      "format_en": "match sentence to picture",
      "answered": 655,
      "wrong_pct": 11.6
    },
    {
      "level": 2,
      "section": "listening",
      "part": 4,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog panjang",
      "format_en": "long dialogue, pick the answer",
      "answered": 93,
      "wrong_pct": 10.8
    },
    {
      "level": 1,
      "section": "listening",
      "part": 3,
      "format_zh": "配图",
      "format_id": "jodohkan dialog–gambar",
      "format_en": "match dialogue to picture",
      "answered": 418,
      "wrong_pct": 10.5
    },
    {
      "level": 1,
      "section": "reading",
      "part": 1,
      "format_zh": "判断对错",
      "format_id": "benar / salah gambar–kata",
      "format_en": "true/false picture–word",
      "answered": 674,
      "wrong_pct": 10.5
    },
    {
      "level": 2,
      "section": "listening",
      "part": 1,
      "format_zh": "判断对错",
      "format_id": "benar / salah dari gambar",
      "format_en": "true/false from picture",
      "answered": 250,
      "wrong_pct": 10.4
    },
    {
      "level": 4,
      "section": "reading",
      "part": 1,
      "format_zh": "选词填空",
      "format_id": "isi kalimat dengan kata dari kotak",
      "format_en": "fill the blank from a word bank",
      "answered": 145,
      "wrong_pct": 9.7
    },
    {
      "level": 4,
      "section": "listening",
      "part": 2,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog pendek",
      "format_en": "short dialogue, pick the answer",
      "answered": 141,
      "wrong_pct": 9.2
    }
  ],
  "exercise_types": [
    {
      "type": "listening_choice",
      "label_id": "Pilihan jawaban mendengar",
      "label_en": "Listening choice",
      "n": 11738,
      "wrong_pct": 17.5
    },
    {
      "type": "rearrange_words",
      "label_id": "Susun kata (tata bahasa)",
      "label_en": "Rearrange words (grammar)",
      "n": 7281,
      "wrong_pct": 15.6
    },
    {
      "type": "multiple_choice",
      "label_id": "Pilihan ganda kosakata",
      "label_en": "Vocabulary multiple choice",
      "n": 18209,
      "wrong_pct": 5.6
    },
    {
      "type": "reading_comprehension",
      "label_id": "Pemahaman bacaan",
      "label_en": "Reading comprehension",
      "n": 6831,
      "wrong_pct": 2.8
    }
  ],
  "missed_words_exercise": [
    {
      "hanzi": "没事",
      "pinyin": "méishì",
      "meaning_id": "nggak apa-apa",
      "meaning_en": "it's fine / no problem",
      "type_id": "frasa/ungkapan",
      "type_en": "set phrase",
      "n": 119,
      "wrong_pct": 20.2
    },
    {
      "hanzi": "想",
      "pinyin": "xiǎng",
      "meaning_id": "berpikir (tentang)",
      "meaning_en": "to want; to think",
      "type_id": "kata kerja modal",
      "type_en": "modal verb",
      "n": 145,
      "wrong_pct": 13.8
    },
    {
      "hanzi": "工作",
      "pinyin": "gōngzuò",
      "meaning_id": "bekerja; pekerjaan",
      "meaning_en": "work; job",
      "type_id": "kata kerja/benda",
      "type_en": "verb/noun",
      "n": 88,
      "wrong_pct": 13.6
    },
    {
      "hanzi": "的",
      "pinyin": "de",
      "meaning_id": "milik (partikel posesif)",
      "meaning_en": "possessive particle",
      "type_id": "partikel",
      "type_en": "particle",
      "n": 88,
      "wrong_pct": 11.4
    },
    {
      "hanzi": "孩子",
      "pinyin": "háizi",
      "meaning_id": "Anak",
      "meaning_en": "child",
      "type_id": "kata benda",
      "type_en": "noun",
      "n": 53,
      "wrong_pct": 11.3
    },
    {
      "hanzi": "哪",
      "pinyin": "nǎ",
      "meaning_id": "mana",
      "meaning_en": "which",
      "type_id": "kata ganti tanya",
      "type_en": "question word",
      "n": 99,
      "wrong_pct": 11.1
    },
    {
      "hanzi": "太",
      "pinyin": "tài",
      "meaning_id": "terlalu",
      "meaning_en": "too (excessively)",
      "type_id": "kata keterangan",
      "type_en": "adverb",
      "n": 101,
      "wrong_pct": 10.9
    },
    {
      "hanzi": "再见",
      "pinyin": "zàijiàn",
      "meaning_id": "sampai jumpa",
      "meaning_en": "goodbye",
      "type_id": "salam/ungkapan",
      "type_en": "greeting",
      "n": 373,
      "wrong_pct": 9.7
    },
    {
      "hanzi": "叫",
      "pinyin": "jiào",
      "meaning_id": "Memanggil / bernama",
      "meaning_en": "to be called",
      "type_id": "kata kerja",
      "type_en": "verb",
      "n": 118,
      "wrong_pct": 9.3
    },
    {
      "hanzi": "吗",
      "pinyin": "ma",
      "meaning_id": "Partikel pertanyaan (ya/tidak)",
      "meaning_en": "question particle",
      "type_id": "partikel",
      "type_en": "particle",
      "n": 99,
      "wrong_pct": 9.1
    },
    {
      "hanzi": "口",
      "pinyin": "kǒu",
      "meaning_id": "mulut",
      "meaning_en": "mouth (also measure word)",
      "type_id": "kata bilangan",
      "type_en": "measure word",
      "n": 62,
      "wrong_pct": 8.1
    },
    {
      "hanzi": "好看",
      "pinyin": "hǎokàn",
      "meaning_id": "cantik; bagus dipandang",
      "meaning_en": "good-looking",
      "type_id": "kata sifat",
      "type_en": "adjective",
      "n": 51,
      "wrong_pct": 7.8
    },
    {
      "hanzi": "新",
      "pinyin": "xīn",
      "meaning_id": "baru",
      "meaning_en": "new",
      "type_id": "kata sifat",
      "type_en": "adjective",
      "n": 52,
      "wrong_pct": 7.7
    },
    {
      "hanzi": "同学",
      "pinyin": "tóngxué",
      "meaning_id": "teman sekelas",
      "meaning_en": "classmate",
      "type_id": "kata benda",
      "type_en": "noun",
      "n": 352,
      "wrong_pct": 7.7
    },
    {
      "hanzi": "谁",
      "pinyin": "shéi",
      "meaning_id": "siapa",
      "meaning_en": "who",
      "type_id": "kata ganti tanya",
      "type_en": "question word",
      "n": 95,
      "wrong_pct": 7.4
    }
  ],
  "missed_words_type_share": {
    "particle": 13.0,
    "noun": 13.0,
    "question word": 13.0,
    "adjective": 13.0,
    "set phrase": 7.0,
    "modal verb": 7.0,
    "verb/noun": 7.0,
    "adverb": 7.0,
    "greeting": 7.0,
    "verb": 7.0,
    "measure word": 7.0
  },
  "forgotten_words_srs": [
    {
      "hanzi": "件",
      "pinyin": "jiàn",
      "meaning_id": "buah (kata bantu)",
      "meaning_en": "measure word for items",
      "type_id": "kata bilangan",
      "type_en": "measure word",
      "cards": 51,
      "lapses_per_card": 0.86,
      "lapsed_share_pct": 27.0
    },
    {
      "hanzi": "饺子",
      "pinyin": "jiǎozi",
      "meaning_id": "pangsit",
      "meaning_en": "dumpling",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 127,
      "lapses_per_card": 0.73,
      "lapsed_share_pct": 23.0
    },
    {
      "hanzi": "玩",
      "pinyin": "wán",
      "meaning_id": "bermain",
      "meaning_en": "to play",
      "type_id": "kata kerja",
      "type_en": "verb",
      "cards": 59,
      "lapses_per_card": 0.73,
      "lapsed_share_pct": 15.0
    },
    {
      "hanzi": "新",
      "pinyin": "xīn",
      "meaning_id": "baru",
      "meaning_en": "new",
      "type_id": "kata sifat",
      "type_en": "adjective",
      "cards": 131,
      "lapses_per_card": 0.65,
      "lapsed_share_pct": 24.0
    },
    {
      "hanzi": "超市",
      "pinyin": "chāoshì",
      "meaning_id": "supermarket",
      "meaning_en": "supermarket (abbr. for 超級市場|超级市场[chao1 ji2 shi4 chang3])",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 101,
      "lapses_per_card": 0.6,
      "lapsed_share_pct": 18.0
    },
    {
      "hanzi": "唱",
      "pinyin": "chàng",
      "meaning_id": "menyanyi",
      "meaning_en": "to sing",
      "type_id": "kata kerja",
      "type_en": "verb",
      "cards": 57,
      "lapses_per_card": 0.6,
      "lapsed_share_pct": 18.0
    },
    {
      "hanzi": "便宜",
      "pinyin": "piányi",
      "meaning_id": "murah",
      "meaning_en": "cheap",
      "type_id": "kata sifat",
      "type_en": "adjective",
      "cards": 57,
      "lapses_per_card": 0.6,
      "lapsed_share_pct": 21.0
    },
    {
      "hanzi": "后",
      "pinyin": "hòu",
      "meaning_id": "setelah",
      "meaning_en": "after; behind",
      "type_id": "kata arah/posisi",
      "type_en": "direction/position word",
      "cards": 76,
      "lapses_per_card": 0.59,
      "lapsed_share_pct": 18.0
    },
    {
      "hanzi": "房间",
      "pinyin": "fángjiān",
      "meaning_id": "kamar",
      "meaning_en": "room",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 70,
      "lapses_per_card": 0.57,
      "lapsed_share_pct": 19.0
    },
    {
      "hanzi": "事",
      "pinyin": "shì",
      "meaning_id": "urusan",
      "meaning_en": "matter; affair",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 70,
      "lapses_per_card": 0.56,
      "lapsed_share_pct": 19.0
    },
    {
      "hanzi": "牛奶",
      "pinyin": "niúnǎi",
      "meaning_id": "susu sapi",
      "meaning_en": "cow's milk",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 100,
      "lapses_per_card": 0.55,
      "lapsed_share_pct": 17.0
    },
    {
      "hanzi": "休息",
      "pinyin": "xiūxi",
      "meaning_id": "istirahat",
      "meaning_en": "rest",
      "type_id": "kata kerja",
      "type_en": "verb",
      "cards": 123,
      "lapses_per_card": 0.53,
      "lapsed_share_pct": 18.0
    },
    {
      "hanzi": "店",
      "pinyin": "diàn",
      "meaning_id": "toko",
      "meaning_en": "shop",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 72,
      "lapses_per_card": 0.49,
      "lapsed_share_pct": 22.0
    },
    {
      "hanzi": "椅子",
      "pinyin": "yǐzi",
      "meaning_id": "kursi",
      "meaning_en": "chair",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 65,
      "lapses_per_card": 0.48,
      "lapsed_share_pct": 20.0
    },
    {
      "hanzi": "前",
      "pinyin": "qián",
      "meaning_id": "depan",
      "meaning_en": "front; before",
      "type_id": "kata benda",
      "type_en": "noun",
      "cards": 64,
      "lapses_per_card": 0.47,
      "lapsed_share_pct": 19.0
    }
  ],
  "paid": {
    "highest_level_studied_pct": {
      "1": 41.1,
      "2": 13.8,
      "3": 8.9,
      "4": 11.2,
      "5": 5.4,
      "6": 2.2,
      "none": 17.4
    },
    "placement_level_pct": {
      "1": 38.0,
      "2": 6.0,
      "3": 29.0,
      "4": 18.0,
      "5": 3.0,
      "6": 6.0
    },
    "paid_share_within_placement_pct": {
      "1": 12.1,
      "2": 14.3,
      "3": 33.3,
      "4": 25.0,
      "5": 6.7,
      "6": 6.5
    },
    "bundle_full_pct": 72.0,
    "single_level_pct": 10.0,
    "lowest_level_2_pct": 84.0,
    "plan_mix_pct": {
      "lifetime": 88.0,
      "monthly": 4.0,
      "annual": 2.0,
      "other": 6.0
    }
  },
  "placement_all_takers_pct": {
    "1": 48.0,
    "2": 6.0,
    "3": 14.0,
    "4": 11.0,
    "5": 7.0,
    "6": 14.0
  },
  "easiest_parts": [
    {
      "level": 4,
      "section": "listening",
      "part": 2,
      "format_zh": "选答案",
      "format_id": "pilih jawaban dialog pendek",
      "format_en": "short dialogue, pick the answer",
      "answered": 141,
      "wrong_pct": 9.2
    },
    {
      "level": 4,
      "section": "reading",
      "part": 1,
      "format_zh": "选词填空",
      "format_id": "isi kalimat dengan kata dari kotak",
      "format_en": "fill the blank from a word bank",
      "answered": 145,
      "wrong_pct": 9.7
    },
    {
      "level": 2,
      "section": "listening",
      "part": 1,
      "format_zh": "判断对错",
      "format_id": "benar / salah dari gambar",
      "format_en": "true/false from picture",
      "answered": 250,
      "wrong_pct": 10.4
    }
  ],
  "format_demand": {
    "tiers": [
      "recognition",
      "retrieval",
      "integration",
      "comprehension"
    ],
    "by_level": [
      {
        "level": 1,
        "tier": "recognition",
        "answered": 2632,
        "wrong_pct": 12.6
      },
      {
        "level": 1,
        "tier": "retrieval",
        "answered": 1041,
        "wrong_pct": 25.3
      },
      {
        "level": 1,
        "tier": "integration",
        "answered": 635,
        "wrong_pct": 24.4
      },
      {
        "level": 2,
        "tier": "recognition",
        "answered": 1035,
        "wrong_pct": 13.9
      },
      {
        "level": 2,
        "tier": "retrieval",
        "answered": 747,
        "wrong_pct": 20.6
      },
      {
        "level": 2,
        "tier": "integration",
        "answered": 264,
        "wrong_pct": 31.1
      },
      {
        "level": 2,
        "tier": "comprehension",
        "answered": 93,
        "wrong_pct": 10.8
      },
      {
        "level": 3,
        "tier": "recognition",
        "answered": 594,
        "wrong_pct": 18.4
      },
      {
        "level": 3,
        "tier": "retrieval",
        "answered": 394,
        "wrong_pct": 13.7
      },
      {
        "level": 3,
        "tier": "integration",
        "answered": 130,
        "wrong_pct": 25.4
      },
      {
        "level": 3,
        "tier": "comprehension",
        "answered": 347,
        "wrong_pct": 16.1
      },
      {
        "level": 4,
        "tier": "recognition",
        "answered": 111,
        "wrong_pct": 13.5
      },
      {
        "level": 4,
        "tier": "retrieval",
        "answered": 141,
        "wrong_pct": 9.2
      },
      {
        "level": 4,
        "tier": "integration",
        "answered": 285,
        "wrong_pct": 21.1
      },
      {
        "level": 4,
        "tier": "comprehension",
        "answered": 440,
        "wrong_pct": 17.3
      },
      {
        "level": 5,
        "tier": "retrieval",
        "answered": 256,
        "wrong_pct": 16.0
      },
      {
        "level": 5,
        "tier": "integration",
        "answered": 115,
        "wrong_pct": 38.3
      },
      {
        "level": 5,
        "tier": "comprehension",
        "answered": 429,
        "wrong_pct": 22.6
      }
    ],
    "pooled": [
      {
        "tier": "recognition",
        "answered": 4372,
        "wrong_pct": 13.7,
        "ratio_vs_recognition": 1.0
      },
      {
        "tier": "retrieval",
        "answered": 2579,
        "wrong_pct": 20.4,
        "ratio_vs_recognition": 1.49
      },
      {
        "tier": "integration",
        "answered": 1429,
        "wrong_pct": 26.2,
        "ratio_vs_recognition": 1.91
      },
      {
        "tier": "comprehension",
        "answered": 1309,
        "wrong_pct": 18.3,
        "ratio_vs_recognition": 1.33
      }
    ],
    "parts_per_tier": {
      "recognition": 12,
      "retrieval": 8,
      "integration": 6,
      "comprehension": 8
    }
  },
  "error_concentration": {
    "parts": {
      "parts_counted": 34,
      "top20pct_parts_share_of_wrong_pct": 44.8,
      "top30pct_parts_share_of_wrong_pct": 59.2,
      "gini_wrong_rate": 0.219
    },
    "hsk1_words": {
      "words_counted": 126,
      "top20pct_words_share_of_wrong_pct": 65.4,
      "top30pct_words_share_of_wrong_pct": 76.1,
      "gini_wrong_rate": 0.522
    }
  },
  "pos_class_error": {
    "classes": {
      "function": "particles, adverbs, pronouns/question words, prepositions, conjunctions, modal verbs",
      "content": "nouns, verbs, adjectives, numerals",
      "measure": "measure words",
      "phrase": "set phrases and greetings"
    },
    "exercise_hsk1": [
      {
        "class": "function",
        "n_words": 29,
        "attempts": 3203,
        "wrong_pct": 5.4,
        "ci95": [
          4.7,
          6.3
        ]
      },
      {
        "class": "content",
        "n_words": 78,
        "attempts": 4859,
        "wrong_pct": 4.7,
        "ci95": [
          4.1,
          5.3
        ]
      },
      {
        "class": "measure",
        "n_words": 7,
        "attempts": 301,
        "wrong_pct": 3.7,
        "ci95": [
          2.1,
          6.4
        ]
      },
      {
        "class": "phrase",
        "n_words": 7,
        "attempts": 1797,
        "wrong_pct": 4.6,
        "ci95": [
          3.7,
          5.7
        ]
      }
    ],
    "exercise_unclassified_words": 4,
    "srs_hsk1": [
      {
        "class": "function",
        "n_words": 62,
        "ci95": [
          5.2,
          6.0
        ],
        "cards": 11214,
        "lapsed_share_pct": 5.6
      },
      {
        "class": "content",
        "n_words": 214,
        "ci95": [
          7.7,
          8.4
        ],
        "cards": 24196,
        "lapsed_share_pct": 8.1
      },
      {
        "class": "measure",
        "n_words": 12,
        "ci95": [
          8.6,
          12.3
        ],
        "cards": 1078,
        "lapsed_share_pct": 10.3
      },
      {
        "class": "phrase",
        "n_words": 8,
        "ci95": [
          5.2,
          6.5
        ],
        "cards": 5129,
        "lapsed_share_pct": 5.8
      }
    ],
    "srs_unclassified_words": 9
  },
  "recognition_recall": {
    "n_words_both": 104,
    "spearman_exercise_vs_srs": 0.261,
    "divergent_share_pct": 19.2,
    "n_words_frequency": 104,
    "spearman_frequency_vs_exercise_wrong": 0.023
  },
  "learnability": {
    "exercise_types": [
      {
        "type": "multiple_choice",
        "learners": 155,
        "wrong_early": 3.4,
        "wrong_late": 6.3,
        "relative_change_pct": 85.3
      },
      {
        "type": "listening_choice",
        "learners": 96,
        "wrong_early": 14.9,
        "wrong_late": 17.5,
        "relative_change_pct": 17.4
      },
      {
        "type": "rearrange_words",
        "learners": 59,
        "wrong_early": 12.2,
        "wrong_late": 22.7,
        "relative_change_pct": 86.1
      },
      {
        "type": "reading_comprehension",
        "learners": 48,
        "wrong_early": 4.8,
        "wrong_late": 2.1,
        "relative_change_pct": -56.2
      }
    ],
    "exam_tiers": [
      {
        "tier": "recognition",
        "first_answered": 1101,
        "later_answered": 2436,
        "wrong_first": 12.8,
        "wrong_later": 14.1,
        "relative_change_pct": 10.2
      },
      {
        "tier": "retrieval",
        "first_answered": 565,
        "later_answered": 1579,
        "wrong_first": 19.8,
        "wrong_later": 21.3,
        "relative_change_pct": 7.6
      },
      {
        "tier": "integration",
        "first_answered": 209,
        "later_answered": 1040,
        "wrong_first": 31.6,
        "wrong_later": 25.3,
        "relative_change_pct": -19.9
      },
      {
        "tier": "comprehension",
        "first_answered": 362,
        "later_answered": 727,
        "wrong_first": 18.8,
        "wrong_later": 17.5,
        "relative_change_pct": -6.9
      }
    ],
    "exam_user_level_pairs_with_repeat": 91,
    "method": "exercise: per learner+type, attempts ordered by created_at, wrong% in attempts 1-10 vs 21+, learners with >=30 attempts; exam: per user+level, first completed attempt vs all later attempts, pooled by demand tier"
  },
  "section_coupling": {
    "n_attempts_both": 30,
    "pearson_r": 0.729,
    "reading_below_listening_pct_by_level": {
      "1": 47.1,
      "2": 100.0,
      "3": 62.5,
      "4": 100.0,
      "5": 50.0
    },
    "reading_below_listening_pct_pooled": 56.7
  },
  "level_wall": {
    "score_definition": "total_score / max_score as stored per attempt (full-paper or single-section mode), writing-only attempts excluded; pass = >= 60%",
    "levels": [
      {
        "level": 1,
        "attempts": 214,
        "pass_rate_pct": 80.8,
        "median": 90.0,
        "p25": 65.0,
        "p75": 100.0
      },
      {
        "level": 2,
        "attempts": 79,
        "pass_rate_pct": 79.7,
        "median": 88.0,
        "p25": 64.0,
        "p75": 92.0
      },
      {
        "level": 3,
        "attempts": 44,
        "pass_rate_pct": 65.9,
        "median": 74.0,
        "p25": 31.5,
        "p75": 93.9
      },
      {
        "level": 4,
        "attempts": 27,
        "pass_rate_pct": 77.8,
        "median": 83.0,
        "p25": 65.0,
        "p75": 90.5
      },
      {
        "level": 5,
        "attempts": 29,
        "pass_rate_pct": 41.4,
        "median": 42.0,
        "p25": 13.0,
        "p75": 82.0
      }
    ]
  },
  "market": {
    "placement_all_takers_pct": {
      "1": 48.4,
      "2": 6.3,
      "3": 13.6,
      "4": 10.9,
      "5": 6.8,
      "6": 14.0
    },
    "placement_paid_pct": {
      "1": 38.2,
      "2": 5.9,
      "3": 29.4,
      "4": 17.6,
      "5": 2.9,
      "6": 5.9
    },
    "paid_share_within_placement_pct": {
      "1": 12.1,
      "2": 14.3,
      "3": 33.3,
      "4": 25.0,
      "5": 6.7,
      "6": 6.5
    },
    "over_under_index": {
      "1": 0.79,
      "2": 0.94,
      "3": 2.16,
      "4": 1.61,
      "5": 0.43,
      "6": 0.42
    },
    "bundle_choice_by_placement_pct": {
      "1": {
        "full_bundle": 69.0,
        "single_level": 8.0,
        "subscription_or_grant": 23.0
      },
      "2": {
        "full_bundle": 50.0,
        "subscription_or_grant": 50.0
      },
      "3": {
        "full_bundle": 80.0,
        "subscription_or_grant": 20.0
      },
      "4": {
        "full_bundle": 67.0,
        "partial": 17.0,
        "single_level": 17.0
      },
      "5": {
        "full_bundle": 100.0
      },
      "6": {
        "single_level": 100.0
      }
    }
  }
}