leaderboard: add significance tiers (repo v1.9 parity)

leaderboard.md

@@ -2,18 +2,20 @@
 
 `translate`/`char-gloss` headline = **Claude Opus 4.7 LLM judge** (0–1); chrF systematically under-rates synonymous paraphrase and is reported as a labelled floor in the transparency table below. `Preserve` = `punctuate` char-preservation rate (fraction of items where the model did not rewrite the text — a fidelity diagnostic `translate` cannot express; see `docs/task-redundancy.md`).
 
-| Model | translate (Judge) | punctuate (Punct F1) | char-gloss (Judge) | idiom-source (Book EM) | fill-in (Exact) | compress (Compress Eff) | Preserve | Avg |
-|---|---|---|---|---|---|---|---|---|
-| claude-opus-4-7 | 0.800 ±0.041 | 0.800 ±0.063 | 0.716 ±0.050 | 0.650 ±0.090 | 0.860 ±0.065 | 0.147 ±0.034 | 0.820 | **0.662 ±0.024** |
-| claude-opus-4-7-thinking | 0.802 ±0.043 | 0.790 ±0.065 | 0.736 ±0.044 | 0.630 ±0.095 | 0.880 ±0.065 | 0.091 ±0.026 | 0.820 | **0.655 ±0.025** |
-| claude-sonnet-4-6 | 0.776 ±0.047 | 0.785 ±0.063 | 0.694 ±0.049 | 0.560 ±0.100 | 0.700 ±0.090 | 0.163 ±0.022 | 0.740 | **0.613 ±0.027** |
-| Qwen3.5-35B-A3B | 0.728 ±0.048 | 0.753 ±0.062 | 0.620 ±0.052 | 0.500 ±0.100 | 0.380 ±0.090 | — | 0.690 | **0.596 ±0.032 ⚠** |
-| glm-5 | 0.748 ±0.045 | 0.799 ±0.063 | 0.638 ±0.055 | 0.740 ±0.085 | 0.450 ±0.100 | 0.153 ±0.018 | 0.790 | **0.588 ±0.026** |
-| minimax-m2.1 | 0.704 ±0.052 | 0.709 ±0.072 | 0.695 ±0.060 | 0.660 ±0.090 | 0.630 ±0.095 | 0.094 ±0.010 | 0.620 | **0.582 ±0.028** |
-| deepseek-3.2 | 0.754 ±0.045 | 0.745 ±0.071 | 0.538 ±0.060 | 0.740 ±0.085 | 0.550 ±0.095 | 0.163 ±0.019 | 0.770 | **0.582 ±0.029** |
-| minimax-m2.5 | 0.704 ±0.047 | 0.709 ±0.068 | 0.654 ±0.057 | 0.550 ±0.095 | 0.590 ±0.095 | 0.092 ±0.009 | 0.620 | **0.550 ±0.029** |
-| qwen3-coder-next | 0.746 ±0.046 | 0.767 ±0.063 | 0.602 ±0.055 | 0.540 ±0.100 | 0.520 ±0.095 | 0.113 ±0.011 | 0.660 | **0.548 ±0.028** |
-| claude-haiku-4-5-20251001 | 0.675 ±0.049 | 0.729 ±0.062 | 0.578 ±0.058 | 0.340 ±0.090 | 0.350 ±0.090 | 0.087 ±0.009 | 0.720 | **0.460 ±0.028** |
+`Tier` = statistical significance band: models sharing a letter have **overlapping 95% Avg CIs** (not significantly different); a lower letter is significantly worse than its tier leader. Treat within-tier order as noise.
+
+| Tier | Model | translate (Judge) | punctuate (Punct F1) | char-gloss (Judge) | idiom-source (Book EM) | fill-in (Exact) | compress (Compress Eff) | Preserve | Avg |
+|---|---|---|---|---|---|---|---|---|---|
+| A | claude-opus-4-7 | 0.800 ±0.041 | 0.800 ±0.063 | 0.716 ±0.050 | 0.650 ±0.090 | 0.860 ±0.065 | 0.147 ±0.034 | 0.820 | **0.662 ±0.024** |
+| A | claude-opus-4-7-thinking | 0.802 ±0.043 | 0.790 ±0.065 | 0.736 ±0.044 | 0.630 ±0.095 | 0.880 ±0.065 | 0.091 ±0.026 | 0.820 | **0.655 ±0.025** |
+| A | claude-sonnet-4-6 | 0.776 ±0.047 | 0.785 ±0.063 | 0.694 ±0.049 | 0.560 ±0.100 | 0.700 ±0.090 | 0.163 ±0.022 | 0.740 | **0.613 ±0.027** |
+| B | Qwen3.5-35B-A3B | 0.728 ±0.048 | 0.753 ±0.062 | 0.620 ±0.052 | 0.500 ±0.100 | 0.380 ±0.090 | — | 0.690 | **0.596 ±0.032 ⚠** |
+| B | glm-5 | 0.748 ±0.045 | 0.799 ±0.063 | 0.638 ±0.055 | 0.740 ±0.085 | 0.450 ±0.100 | 0.153 ±0.018 | 0.790 | **0.588 ±0.026** |
+| B | minimax-m2.1 | 0.704 ±0.052 | 0.709 ±0.072 | 0.695 ±0.060 | 0.660 ±0.090 | 0.630 ±0.095 | 0.094 ±0.010 | 0.620 | **0.582 ±0.028** |
+| B | deepseek-3.2 | 0.754 ±0.045 | 0.745 ±0.071 | 0.538 ±0.060 | 0.740 ±0.085 | 0.550 ±0.095 | 0.163 ±0.019 | 0.770 | **0.582 ±0.029** |
+| B | minimax-m2.5 | 0.704 ±0.047 | 0.709 ±0.068 | 0.654 ±0.057 | 0.550 ±0.095 | 0.590 ±0.095 | 0.092 ±0.009 | 0.620 | **0.550 ±0.029** |
+| B | qwen3-coder-next | 0.746 ±0.046 | 0.767 ±0.063 | 0.602 ±0.055 | 0.540 ±0.100 | 0.520 ±0.095 | 0.113 ±0.011 | 0.660 | **0.548 ±0.028** |
+| C | claude-haiku-4-5-20251001 | 0.675 ±0.049 | 0.729 ±0.062 | 0.578 ±0.058 | 0.340 ±0.090 | 0.350 ±0.090 | 0.087 ±0.009 | 0.720 | **0.460 ±0.028** |
 
 ⚠ Avg is the mean of *available* task headlines — not strictly comparable for: `Qwen3.5-35B-A3B` missing compress. Excluding a low-scoring task (e.g. `compress`) inflates that model's Avg.