legex/analysis/report.py

"""Render the IAA / Alternative Annotator Test / evaluation CSVs into a minimal ANALYSIS.md.

This is a convenience script, it reads the artifacts produced by
``legex-iaa`` (``pairwise_agreement.csv``), by the Alternative Annotator Test
reference adapter ``scripts/alt_test_reference.py``
(``alt_test_reference_*.csv``, see the README section "Alternative Annotator
Test (AAT)"), by ``scripts/alt_test_decomposition.py``
(``alt_test_decomposition.csv``), and by ``legex-analysis`` (``per_column.csv``), and emits
headers, always-true methodology notes, and live tables. Regenerate the whole
chain with ``scripts/reproduce_paper.sh``.

Usage
-----
    uv run legex-analysis-report
    uv run python -m legex.analysis.report --iaa-dir data/analysis/iaa
"""

import argparse
import csv
import math
import statistics
from pathlib import Path

from legex.analysis.countries import COUNTRY_NAMES

_BUCKETS = ("tp", "mismatch", "missed", "hallucinated", "tn")


# IO helpers
def _read_csv(path: Path) -> list[dict[str, str]]:
    if not path.exists():
        return []
    with path.open(encoding="utf-8", newline="") as f:
        return list(csv.DictReader(f))


def _short_model(model: str) -> str:
    """Display label for a litellm id (drop the provider prefix)."""
    return model.split("/")[-1]


def _country_name(cc: str) -> str:
    return COUNTRY_NAMES.get(cc, cc.upper())


def _md_table(headers: list[str], rows: list[list[str]]) -> str:
    head = "| " + " | ".join(headers) + " |"
    sep = "| " + " | ".join("---" for _ in headers) + " |"
    body = "\n".join("| " + " | ".join(r) + " |" for r in rows)
    return "\n".join([head, sep, body]) if rows else head + "\n" + sep + "\n| _(no data)_ |"


def _se(p: float, n: int) -> float:
    """Binomial standard error of a proportion (1σ of the estimate)."""
    return math.sqrt(p * (1 - p) / n) if n > 0 else 0.0


def _pct_se(p: float, n: int) -> str:
    """Percent with ±1 SE in percentage points, e.g. '49.2% ±3.3'."""
    return f"{p:.1%} ±{_se(p, n) * 100:.1f}"


def _by_field_grid(
    per_column: list[dict[str, str]],
    models: list[str],
    metric_key: str,
    *,
    n_buckets: tuple[str, ...] | None,
    pct: bool = True,
) -> str:
    """Field × model grid for one derived metric.

    ``n_buckets`` sums the bucket columns giving the metric's model-independent
    denominator (shown as ``n``); pass ``None`` when the denominator is
    model-dependent (precision) or composite (F1) so ``n`` is omitted.
    """
    fields = sorted({r["column"] for r in per_column})
    val = {(r["model"], r["column"]): r.get(metric_key, "") for r in per_column}
    n_by_field: dict[str, int] = {}
    if n_buckets:
        for r in per_column:
            tot = sum(int(r[b]) for b in n_buckets)
            n_by_field[r["column"]] = max(n_by_field.get(r["column"], 0), tot)
    rows = []
    for field in fields:
        row = [f"`{field}`"]
        if n_buckets:
            row.append(str(n_by_field.get(field, 0)))
        for m in models:
            v = val.get((m, field), "")
            if v in (None, ""):
                row.append("–")
            else:
                row.append(f"{float(v):.1%}" if pct else f"{float(v):.3f}")
        rows.append(row)
    headers = ["Field"] + (["n"] if n_buckets else []) + [_short_model(m) for m in models]
    return _md_table(headers, rows)


# Variables with a fixed controlled vocabulary -> Cohen's kappa is valid.
_CATEGORICAL_FIELDS = {
    "plaintiff_no1_ISIC1_industry_category",
    "defendant_no1_ISIC1_industry_category",
}

# Measurement level per variable, shown in the by-variable table.
_FIELD_TYPE = {
    "plaintiff_no1_ISIC1_industry_category": "nominal",
    "defendant_no1_ISIC1_industry_category": "nominal",
    "legal_subject_judgement": "free text",
    "trial_start_date": "date",
    "trial_end_date": "date",
    "plaintiffs_all_count": "count",
    "defendants_all_count": "count",
    "dispute_value_nominal": "monetary",
    "court_cost_awarded_nominal": "monetary",
    "party_compensation_awarded_nominal": "monetary",
    "plaintiff_loosing_share": "ratio",
}
_TYPE_ORDER = {
    t: i for i, t in enumerate(
        ["nominal", "free text", "date", "count", "monetary", "ratio", "other"]
    )
}


# Section builders
def _scope(pairwise: list[dict[str, str]]) -> str:
    annotators = {r["annotator_a"] for r in pairwise} | {r["annotator_b"] for r in pairwise}
    pairs = {(r["country"], r["annotator_a"], r["annotator_b"]) for r in pairwise}
    countries = sorted({r["country"] for r in pairwise})
    legend = ", ".join(f"**{cc}** {_country_name(cc)}" for cc in countries)
    secondary = sorted(a for a in annotators if a != "primary")
    lines = [
        "## 1. Scope",
        "",
        f"- Countries with ≥2 annotators: **{len(countries)}** — {', '.join(countries) or '(none)'}",
        f"- Annotators: **{len(annotators)}** (primary + {len(secondary)} secondary: "
        f"{', '.join(secondary) or '(none)'})",
        f"- Annotator pairs (country × pair): **{len(pairs)}**",
        "",
        f"Countries: {legend}." if legend else "",
    ]
    return "\n".join(lines)


def _agreement_sections(pairwise: list[dict[str, str]]) -> str:
    note = (
        "> **Per-variable agreement.** Percent agreement is reported for every variable, using the "
        "same value-matching as the evaluation (ISO-date / number-format aware; `0` and empty treated "
        "alike). For the two **nominal ISIC** fields — the only variables with a fixed controlled "
        "vocabulary — we additionally report **Cohen's κ**. For the other variables the category space "
        "is unbounded (free text) or continuous (dates, counts, money, ratios): there κ's chance "
        "correction collapses toward percent agreement (as the number of categories → ∞, expected "
        "agreement pₑ → 0 and κ → observed agreement) and awards no partial credit for near-misses, so "
        "percent agreement is the appropriate summary. Correlation coefficients are deliberately not "
        "used — for these labels a wrong value is wrong, not partially correct. Cell detail: "
        "`kappa_audit.csv`."
    )
    out = [
        "## 2. Human–human agreement", "", note, "",
        "_n = paired case comparisons (shared cases × annotator pairs). We report ±1 SE = √(p(1-p)/n) in "
        "percentage points, a descriptive precision marker. This is not a significance test._", "",
    ]

    by_pair: dict[tuple[str, str, str], list[dict[str, str]]] = {}
    for r in pairwise:
        by_pair.setdefault((r["country"], r["annotator_a"], r["annotator_b"]), []).append(r)
    # Shared cases per pair (constant across that pair's fields)
    pair_cases = {k: int(v[0]["n"]) for k, v in by_pair.items()}

    def _agg(rows: list[dict[str, str]]) -> tuple[int, float, float]:
        """(total paired observations, n-weighted tolerant %, mean defined κ)."""
        n = sum(int(r["n"]) for r in rows)
        tol = sum(float(r["pct_tolerant"]) * int(r["n"]) for r in rows) / n if n else 0.0
        kv = [float(r["cohen_kappa"]) for r in rows if r.get("cohen_kappa") not in (None, "")]
        mk = statistics.mean(kv) if kv else float("nan")
        return n, tol, mk

    # 2.1 by variable — % for all, κ only for the categorical (fixed-vocab) fields
    out += ["### 2.1 By variable", ""]
    by_field: dict[str, list[dict[str, str]]] = {}
    for r in pairwise:
        by_field.setdefault(r["field"], []).append(r)
    order = sorted(
        by_field,
        key=lambda f: (_TYPE_ORDER.get(_FIELD_TYPE.get(f, "other"), 99), -_agg(by_field[f])[1]),
    )
    var_rows = []
    for field in order:
        n, tol, mk = _agg(by_field[field])
        kappa = f"{mk:.3f}" if (field in _CATEGORICAL_FIELDS and mk == mk) else "—"
        var_rows.append([f"`{field}`", _FIELD_TYPE.get(field, "other"), str(n), _pct_se(tol, n), kappa])
    out.append(_md_table(["Variable", "Type", "n", "% agreement", "Cohen's κ"], var_rows))

    # 2.2 by country
    out += ["", "### 2.2 By country", ""]
    by_cc: dict[str, list[dict[str, str]]] = {}
    for r in pairwise:
        by_cc.setdefault(r["country"], []).append(r)
    cc_rows = []
    for cc in sorted(by_cc):
        pairs = {(r["annotator_a"], r["annotator_b"]) for r in by_cc[cc]}
        n_cases = sum(pair_cases[(cc, a, b)] for (a, b) in pairs)
        _n, tol, _mk = _agg(by_cc[cc])
        cc_rows.append([cc, str(len(pairs)), str(n_cases), f"{tol:.1%}"])
    out.append(_md_table(["Country", "Pairs", "n", "% agreement"], cc_rows))

    # 2.3 by pair
    out += ["", "### 2.3 By pair", ""]
    pair_rows = []
    for (cc, a, b) in sorted(by_pair):
        _n, tol, _mk = _agg(by_pair[(cc, a, b)])
        pair_rows.append([cc, f"{a} – {b}", str(pair_cases[(cc, a, b)]), f"{tol:.1%}"])
    out.append(_md_table(["Country", "Pair", "n", "% agreement"], pair_rows))
    return "\n".join(out)


_ALT_TEST_FORMULA = """### 3.1 How ω and ρ are computed

_Definitions from Calderon et al. (2025), as implemented in the authors' `alt_test`.
`values_agree` is the tolerant comparator LEGEX passes in as the scoring function._

```text
One jurisdiction, one candidate f, human annotators H = {1..M}, and instances i
(here: one (judgment, variable) cell over the 10 structured fields).

LEAVE-ONE-OUT. For human j and every instance i the other humans also labelled,
let A(i,-j) be the remaining humans' labels and

    s_f(i,j) = score( f(i),    A(i,-j) )      candidate vs. the other humans
    s_h(i,j) = score( h_j(i),  A(i,-j) )      held-out human vs. the same humans

    score(p, A) = (1/|A|) * SUM_{a in A} values_agree(p, a)     in {0, 1/2, 1}

ADVANTAGE PROBABILITY of the candidate against human j. Note the ">=", which
credits every tie to the candidate:

    rho_j = (1/n_j) * SUM_i  1[ s_f(i,j) >= s_h(i,j) ]

PER-ANNOTATOR TEST. With d_i = 1[s_f < s_h] - 1[s_f >= s_h], so E[d] = 1 - 2*rho_j:

    H0: E[d] >= epsilon        vs.        H1: E[d] < epsilon

one-sided paired t-test (Wilcoxon signed-rank when n_j < 30), the M p-values
corrected by Benjamini-Yekutieli at q = 0.05. Rejecting H0 is therefore
equivalent to rho_j being significantly greater than

    (1 - epsilon) / 2  =  0.4        for the expert tolerance epsilon = 0.2

VERDICT.

    omega = |{ j : H0_j rejected }| / M          winning rate
    rho   = (1/M) * SUM_j rho_j                  advantage probability
    "f may substitute a human annotator"  <=>  omega >= 0.5
```

Two consequences worth keeping in view when reading §3.2. First, ρ is a
**≥**-comparison, so a candidate that merely matches the held-out human on an
instance is scored as winning it. Second, with ε = 0.2 the hypothesis test
clears at ρ_j > 0.4, not at 0.5. Both are deliberate: the alt-test asks whether
a candidate can *substitute* a human annotator, not whether it is *better* than
one. §3.4 separates the two.
"""


def _alt_test_section(iaa_dir: Path) -> str:
    # Only the reference-implementation outputs are rendered
    files = sorted(p for p in iaa_dir.glob("alt_test_reference_*.csv"))
    rows_by_cand: dict[str, list[dict[str, str]]] = {}
    for p in files:
        for r in _read_csv(p):
            rows_by_cand.setdefault(r["candidate"], []).append(r)
    all_rows = [r for rs in rows_by_cand.values() for r in rs]
    note = (
        "> **Alternative Annotator Test** (Calderon et al. 2025, "
        "[arXiv:2501.10970](https://arxiv.org/abs/2501.10970)): leave each human annotator out in "
        "turn and score, per instance, both the candidate and the excluded annotator against the "
        "remaining annotators; a one-sided test per annotator asks whether the candidate's "
        "advantage probability trails the human's by less than ε = 0.2 (the expert-annotator "
        "tolerance), under Benjamini–Yekutieli FDR control at q = 0.05. `passes` = winning rate "
        "≥ 0.5. Requires ≥ 3 independent annotators per country; free-text fields are excluded. "
        "ρ is the advantage probability — how likely the candidate annotates as well as or better "
        "than a randomly chosen human. The *non-trivial* variant drops instances every expert left "
        "empty: an empty prediction ties those for free, so the gap between the two columns shows "
        "how much of a pass rests on empty cells. Untestable cells (too few non-empty judgements) "
        "are excluded from the denominators.\n>\n"
        "> These numbers come from the **authors' reference implementation** "
        "([github.com/nitaytech/AltTest](https://github.com/nitaytech/AltTest)) executed on the "
        "LEGEX data via `scripts/alt_test_reference.py`. See the README section \"Alternative "
        "Annotator Test (AAT)\" for how to run it. `legex-iaa` does not produce these CSVs."
    )
    out = ["## 3. Alternative-annotator test", "", note, "", _ALT_TEST_FORMULA, ""]

    # 3.2 Headline: pooled per jurisdiction (instance = judgment x variable cell,
    # the SummEval convention of the paper) — this is what the manuscript reports.
    pooled_csv = iaa_dir / "alt_test_pooled.csv"
    if pooled_csv.exists():
        pooled = _read_csv(pooled_csv)
        out += [
            "### 3.2 Headline: pooled per jurisdiction (paper numbers)",
            "",
            "_One alt-test per jurisdiction; instance = (judgment, variable) cell over the"
            " 10 structured fields, so each annotator contributes ~190+ effective instances"
            " and the paired t-test applies without the paper's n<30 caveat._",
            "",
            "| Candidate | Country | ω | ρ | ω (non-triv) | ρ (non-triv) |",
            "| --- | --- | --- | --- | --- | --- |",
        ]
        for r in pooled:
            out.append(
                f"| {r['candidate']} | {r['country']} | {float(r['omega']):.2f}"
                f" | {float(r['rho']):.2f} | {float(r['omega_nontrivial']):.2f}"
                f" | {float(r['rho_nontrivial']):.2f} |"
            )
        out.append("")

    out += ["### 3.3 Per-field diagnostic (cells passed / testable)", ""]
    if not rows_by_cand:
        out.append("_No `alt_test_reference_*.csv` found — run `scripts/alt_test_reference.py` (see README)._")
        return "\n".join(out + ["", _decomposition_section(iaa_dir)])
    countries = sorted({r["country"] for r in all_rows})

    def _rate(rows: list[dict[str, str]], key: str) -> str:
        rows = [r for r in rows if r[key] != ""]
        if not rows:
            return "–"
        p = sum(int(r[key]) for r in rows)
        return f"{p}/{len(rows)}"

    def _mean_rho(rows: list[dict[str, str]], key: str) -> str:
        vals = [float(r[key]) for r in rows if r[key] != ""]
        return f"{statistics.mean(vals):.2f}" if vals else "–"

    headers = [
        "Candidate", "ρ̄ (all)", "Pass (all)", "ρ̄ (non-triv)", "Pass (non-triv)",
        *(f"{cc} (all · non-triv)" for cc in countries),
    ]
    table_rows = []
    for cand in sorted(rows_by_cand):
        rs = rows_by_cand[cand]
        row = [
            _short_model(cand),
            _mean_rho(rs, "advantage_probability"),
            _rate(rs, "passes"),
            _mean_rho(rs, "advantage_probability_nontrivial"),
            _rate(rs, "passes_nontrivial"),
        ]
        for cc in countries:
            sub = [r for r in rs if r["country"] == cc]
            row.append(f"{_rate(sub, 'passes')} · {_rate(sub, 'passes_nontrivial')}")
        table_rows.append(row)
    out.append(_md_table(headers, table_rows))

    out += [
        "",
        "> Per-cell winning rates and advantage probabilities are in "
        "`alt_test_reference_<model>.csv`; an empty cell there means the "
        "(country, field, variant) combination was untestable.",
        "",
        _decomposition_section(iaa_dir),
    ]
    return "\n".join(out)


def _decomposition_section(iaa_dir: Path) -> str:
    """§3.4 — the win/tie/loss counts ρ is built from (substitutable vs. better)."""
    rows = _read_csv(iaa_dir / "alt_test_decomposition.csv")
    out = ["### 3.4 Substitutable vs. better: win / tie / loss decomposition", ""]
    if not rows:
        out.append(
            "_No `alt_test_decomposition.csv` found — run "
            "`uv run python scripts/alt_test_decomposition.py`._"
        )
        return "\n".join(out)

    note = (
        "> ρ collapses the leave-one-out comparison of §3.1 into one number, and its `≥` "
        "hands every tie to the candidate. This section keeps the same comparisons and "
        "reports the counts instead: per held-out human and instance, whether the candidate "
        "scored **better than**, **the same as**, or **worse than** that human against the two "
        "remaining humans. Restricted to judgments all three experts labelled, so every "
        "comparison has exactly two references and a score is 0, ½ or 1. `ρ (alt-test)` is the "
        "reproduced advantage probability (ties → candidate); `ρ (ties split)` counts a tie as "
        "half a win for each side. Source: `alt_test_decomposition.csv` from "
        "`scripts/alt_test_decomposition.py`, which reproduces the reference ρ of §3.2 to "
        "within 0.02."
    )
    out += [note, ""]

    def _pool(candidate: str, variant: str) -> dict[str, int]:
        keys = (
            "n_comparisons", "refs_disagree", "llm_better", "human_better",
            "tie", "tie_same", "tie_diff", "tie_at_1", "tie_at_half", "tie_at_0",
        )
        totals = dict.fromkeys(keys, 0)
        for r in rows:
            if r["candidate"] == candidate and r["variant"] == variant:
                for k in keys:
                    totals[k] += int(r[k])
        return totals

    candidates = sorted({r["candidate"] for r in rows})
    countries = sorted({r["country"] for r in rows})
    headers = [
        "Candidate", "Country", "n", "Candidate better", "Tie", "Human better",
        "ρ (alt-test)", "ρ (ties split)",
    ]
    table: list[list[str]] = []
    for cand in candidates:
        for cc in [*countries, "pooled"]:
            if cc == "pooled":
                t = _pool(cand, "all")
                n = t["n_comparisons"]
                if not n:
                    continue
                cells = [t["llm_better"], t["tie"], t["human_better"]]
                rho_alt = (t["llm_better"] + t["tie"]) / n
                rho_split = (t["llm_better"] + t["tie"] / 2) / n
                label = "**all three**"
            else:
                r = next(
                    (r for r in rows if r["candidate"] == cand
                     and r["country"] == cc and r["variant"] == "all"),
                    None,
                )
                if r is None:
                    continue
                n = int(r["n_comparisons"])
                cells = [int(r["llm_better"]), int(r["tie"]), int(r["human_better"])]
                rho_alt = float(r["rho_alttest"])
                rho_split = float(r["rho_tiebroken"])
                label = cc
            table.append([
                _short_model(cand), label, str(n),
                *(f"{c} ({c / n:.0%})" for c in cells),
                f"{rho_alt:.2f}", f"{rho_split:.2f}",
            ])
    out.append(_md_table(headers, table))

    # What a "tie" actually contains — the bucket ρ is most sensitive to.
    pooled_all = {c: _pool(c, "all") for c in candidates}
    refs_disagree = next(
        (t["refs_disagree"], t["n_comparisons"]) for t in pooled_all.values()
    )
    out += [
        "",
        "**What is in the “Tie” bucket.** A tie only means *same score against the same two "
        "references*, so it merges several different situations. Split by score level, and "
        "independently by whether the candidate actually produced the held-out expert's answer:",
        "",
    ]
    tie_headers = [
        "Candidate", "Ties", "Same answer as expert", "Different answer, equal score",
        "at 1 (all agree)", "at ½ (experts conflict)", "at 0 (both differ)",
    ]
    tie_rows = []
    for cand in candidates:
        t = pooled_all[cand]
        ties = t["tie"]
        if not ties:
            continue
        tie_rows.append([
            _short_model(cand), str(ties),
            *(f"{t[k]} ({t[k] / ties:.0%})" for k in
              ("tie_same", "tie_diff", "tie_at_1", "tie_at_half", "tie_at_0")),
        ])
    out.append(_md_table(tie_headers, tie_rows))
    out += [
        "",
        f"A tie at ½ is only possible when the two reference experts contradict each other — "
        f"that caps every achievable score at ½, for the candidate and the held-out expert "
        f"alike. The two references disagree in {refs_disagree[0]} of {refs_disagree[1]} "
        f"comparisons ({refs_disagree[0] / refs_disagree[1]:.0%}; a property of the human "
        f"labels, identical for every candidate). Note that reference disagreement is *not* "
        f"the same thing as a tie: ties also arise, and in fact more often, where the two "
        f"references agree and the candidate simply matches them.",
    ]

    # Reading: who wins the decisive comparisons.
    lines = []
    for cand in candidates:
        t = pooled_all[cand]
        nt = _pool(cand, "nontrivial")
        n, ties = t["n_comparisons"], t["tie"]
        decisive = t["llm_better"] + t["human_better"]
        if not (n and ties and decisive):
            continue
        nontrivial = (
            f" Dropping instances whose reference is empty throughout leaves ρ (ties split) at "
            f"{(nt['llm_better'] + nt['tie'] / 2) / nt['n_comparisons']:.2f}."
            if nt["n_comparisons"] else ""
        )
        lines.append(
            f"- **{_short_model(cand)}** — {ties / n:.0%} of the {n} comparisons are ties. "
            f"{t['tie_same'] / ties:.0%} of those ties are real agreement (candidate gave the "
            f"held-out expert's answer); the other {t['tie_diff'] / ties:.0%} are comparisons "
            f"where candidate and expert gave *different* answers that happened to score the "
            f"same, and ρ credits every one of them to the candidate. On the {decisive} "
            f"comparisons that actually discriminate, the human wins "
            f"{t['human_better'] / decisive:.0%} ({t['human_better']} vs "
            f"{t['llm_better']}).{nontrivial}"
        )
    if lines:
        out += ["", "**Reading.**", "", *lines]

    out += [
        "",
        "This is what the alt-test is and is not evidence for. The tie rate is high and mostly "
        "genuine, so on this data the models are largely *indistinguishable* from an additional "
        "expert — which is exactly the substitutability claim ω and ρ are designed to support, "
        "and §3.2 supports it. It is not evidence of superiority: once ties stop counting as "
        "wins, ρ sits at chance, and on the comparisons that separate the two the human expert "
        "is still ahead. \"Can this model replace a human annotator?\" and \"is this model better "
        "than a human annotator?\" are different questions, and only the first one is being "
        "tested.",
    ]
    return "\n".join(out)


def _headline_section(per_column: list[dict[str, str]]) -> str:
    note = (
        "> Recall = TP / (TP + Mismatch + Missed) over cells the expert filled; precision = "
        "TP / (TP + Mismatch + Hallucinated); hallucination = invented values on empty-gold cells. "
        "Buckets from `legex/evaluation.py`; per-cell source `../per_column.csv`. n = evaluated "
        "label cells; recall and precision carry ±1 SE over their gold-filled / emitted denominators. "
        "The per-field grids (§4.2–4.5) break each metric out by variable across models; their `n` is "
        "the metric's model-independent denominator (gold-filled for recall, gold-empty for "
        "hallucination) and is omitted for precision (emitted; model-dependent) and F1 (composite)."
    )
    out = ["## 4. Headline extraction metrics", "", note, ""]
    if not per_column:
        out.append("_`../per_column.csv` not found — run `legex-analysis`._")
        return "\n".join(out)

    by_model: dict[str, list[dict[str, str]]] = {}
    for r in per_column:
        by_model.setdefault(r["model"], []).append(r)

    # 4.1 overall, summed across fields & countries
    out += ["### 4.1 Overall (all countries, summed across fields)", ""]
    rows = []
    for model in sorted(by_model):
        b = {k: sum(int(r[k]) for r in by_model[model]) for k in _BUCKETS}
        tp, mism, miss, hallu, tn = (b[k] for k in _BUCKETS)
        total = tp + mism + miss + hallu + tn
        recall = tp / (tp + mism + miss) if (tp + mism + miss) else 0.0
        prec = tp / (tp + mism + hallu) if (tp + mism + hallu) else 0.0
        acc = (tp + tn) / total if total else 0.0
        hallu_rate = hallu / (hallu + tn) if (hallu + tn) else 0.0
        f1 = 2 * prec * recall / (prec + recall) if (prec + recall) else 0.0
        filled = tp + mism + miss
        emitted = tp + mism + hallu
        rows.append([
            _short_model(model), str(total), f"{acc:.1%}",
            _pct_se(recall, filled), _pct_se(prec, emitted),
            f"{hallu_rate:.1%}", f"{f1:.3f}",
        ])
    out.append(_md_table(
        ["Model", "n", "Accuracy", "Recall (filled)", "Precision", "Hallu. rate", "F1"], rows
    ))

    # 4.2–4.5 per-field grids (Field × model) for each metric
    models = sorted(by_model)
    out += ["", "### 4.2 Recall (filled) by field (all countries)", ""]
    out.append(_by_field_grid(per_column, models, "recall_when_filled",
                              n_buckets=("tp", "mismatch", "missed")))
    out += ["", "### 4.3 Precision by field (all countries)", ""]
    out.append(_by_field_grid(per_column, models, "precision_when_emitted", n_buckets=None))
    out += ["", "### 4.4 Hallucination rate by field (all countries)", ""]
    out.append(_by_field_grid(per_column, models, "hallucination_rate",
                              n_buckets=("hallucinated", "tn")))
    out += ["", "### 4.5 F1 by field (all countries)", ""]
    out.append(_by_field_grid(per_column, models, "f1", n_buckets=None, pct=False))
    return "\n".join(out)


def _appendix() -> str:
    return "\n".join([
        "## Appendix",
        "",
        "### Landis–Koch (1977) κ scale (for interpreting the ISIC κ)",
        "",
        _md_table(
            ["κ", "Strength"],
            [
                ["< 0.00", "Poor (worse than chance)"],
                ["0.00 – 0.20", "Slight"],
                ["0.21 – 0.40", "Fair"],
                ["0.41 – 0.60", "Moderate"],
                ["0.61 – 0.80", "Substantial"],
                ["0.81 – 1.00", "Almost perfect"],
            ],
        ),
        "",
        "### Provenance",
        "",
        "- Pairwise agreement & kappa: `legex/analysis/iaa.py` (`pairwise_agreement`, "
        "`write_kappa_audit_csv`).",
        "- Alt-test: authors' reference implementation "
        "([github.com/nitaytech/AltTest](https://github.com/nitaytech/AltTest)) run via "
        "`scripts/alt_test_reference.py` → `alt_test_reference_*.csv` (see README).",
        "- Alt-test win/tie/loss decomposition: `scripts/alt_test_decomposition.py` → "
        "`alt_test_decomposition.csv`.",
        "- Tolerant comparator: `legex/evaluation/comparison.py` (`values_agree`, `normalise`).",
        "- Headline buckets: `legex/analysis/aggregate.py` over `legex/evaluation.score_country`.",
        "- This report: `legex/analysis/report.py`.",
    ])


def build_report(iaa_dir: Path, analysis_dir: Path) -> str:
    pairwise = _read_csv(iaa_dir / "pairwise_agreement.csv")
    per_column = _read_csv(analysis_dir / "per_column.csv")
    header = [
        "# Inter-Annotator Agreement & Alternative-Annotator Test",
        "",
        "_Generated by `legex-analysis-report` from the CSVs in this directory — do not edit by "
        "hand; numbers always reflect the current CSVs._",
        "",
        "Regenerate the whole chain with `scripts/reproduce_paper.sh`.",
        "",
        "---",
        "",
    ]
    parts = [
        "\n".join(header),
        _scope(pairwise),
        _agreement_sections(pairwise),
        _alt_test_section(iaa_dir),
        _headline_section(per_column),
        _appendix(),
    ]
    return "\n\n".join(p.strip() for p in parts) + "\n"


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(
        prog="legex-analysis-report",
        description="Render the IAA / alt-test / evaluation CSVs into a minimal ANALYSIS.md.",
    )
    parser.add_argument(
        "--iaa-dir", type=Path, default=Path("data/analysis/iaa"),
        help="Directory with pairwise_agreement.csv (from legex-iaa) and "
             "alt_test_reference_*.csv (from scripts/alt_test_reference.py), "
             "and the output ANALYSIS.md.",
    )
    parser.add_argument(
        "--analysis-dir", type=Path, default=Path("data/analysis"),
        help="Directory with per_column.csv (from legex-analysis).",
    )
    parser.add_argument(
        "--out", type=Path, default=None,
        help="Output path (default: <iaa-dir>/ANALYSIS.md).",
    )
    args = parser.parse_args(argv)
    out = args.out or (args.iaa_dir / "ANALYSIS.md")
    out.parent.mkdir(parents=True, exist_ok=True)
    out.write_text(build_report(args.iaa_dir, args.analysis_dir), encoding="utf-8")
    print(f"wrote {out}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())