v6: README.md

README.md

@@ -7,17 +7,24 @@ task_categories:
 - visual-question-answering
 language:
 - en
-pretty_name: BenchCheck meta-benchmark (v5)
+pretty_name: BenchCheck meta-benchmark (v6)
 size_categories:
 - n<1K
+configs:
+- config_name: meta_benchmark
+  data_files: items/meta_benchmark.jsonl
+  default: true
+- config_name: coverage_census
+  data_files: items/coverage_census.jsonl
 ---
-# BenchCheck meta-benchmark (v5)
+# BenchCheck meta-benchmark (v6)
 
 840 multiple-choice video questions from 76 public video benchmarks, one item per video,
 four capability groups x 210 (Perception, Temporal, Spatial / physical, Reasoning / knowledge). The set is the
 difficulty-first census of the BenchCheck screened pool: items that none of the cheap attackers of the pool screening
 (text-only, single frame, 32-frame 2B model, options-only, shuffled frames) could solve, ranked by the worst-case attacker
-percentile, with the marked answers verified against the frames and the reference model's share of correct answers capped.
+percentile, with the marked answers verified against the frames; no cap on any model's accuracy (v6, 2026-09-19: the earlier
+v5 composition capped the reference model's share of correct answers at 45 %, the cap is dropped so that every row of the leaderboard is a measurement).
 
 ## Construction (five steps; details in the paper appendix)
 1. Candidates: the screened pool; the 3,000 items with the smallest worst-case attacker percentile (one per video).
@@ -28,25 +35,28 @@ percentile, with the marked answers verified against the frames and the referenc
    supported; reversed clips (AoTBench RTime, TempCompass direction); not verifiable on videos >= 60 s. Dropped:
    contradicted; definition dependent; not verifiable on videos < 60 s. Ordering questions whose options are the events
    themselves are excluded (not scorable as single choice).
-3b. Selection with a reference cap: per group the verified items in worst-case percentile order until 210, with at most
-   94 (45%) that the reference model (Claude Opus 5, VIDEO protocol) answers correctly.
+3b. Selection: per group the verified items in worst-case attacker percentile order (hardest first) until 210, one item per
+   video, no reference cap. The reference model (Claude Opus 5, VIDEO protocol) answers 56.8 % of the resulting items; this is reported, not constrained.
 4. Protocols: VIDEO (1 fps, <= 512 frames, short side 224) and BLIND (question + options, 4 permutations); see code/prompt.md.
 
-Version v5: final composition.
+Version v6: final composition.
 
 ## Files
+- `items/coverage_census.jsonl`: the coverage census used as the appendix comparison (832 items, at most 8 per benchmark from
+  106 benchmarks, one per video where possible; same fields without the verification).
 - `items/meta_benchmark.jsonl`: one line per item (fields: item_id, benchmark, capability_group, fine_category, question,
   options, answer, answer_idx, chance, video, video_id, duration_s, attack_pct, verification, source_version, license).
 - `items/summary.json`: counts per group, benchmark and verification reason.
 - `videos/<video_id>.mp4`: normalized videos (840 files; H.264, at most 1,024 stored frames per video).
-- `code/prompt.md`: the exact prompts and the scoring rule.
+- `code/prompt.md`: the exact prompts, the frame sampling rule (1 fps over the timeline, at most 512 frames uniformly thinned,
+  short side 224; the stored videos hold at most 1,024 frames) and the scoring rule.
 - `results/leaderboard.csv`: current leaderboard (Overall = VIDEO, Blind, Gain, per-group accuracy; n = items scored).
 
 ## Composition
-Groups: {'perception': 210, 'temporal': 210, 'spatial_physical': 210, 'reasoning_knowledge': 210}. Largest sources: {'S-EMBER': 120, 'AoTBench': 87, 'ALLVB': 45, 'UrbanVideo-Bench': 34, 'TOC-Bench': 32, 'Video-MME-v2': 31, 'Camera Movement Understanding (BU_Google)': 31, 'VideoOdyssey': 30}.
-Verification reasons: {'reversed_clip': 85, 'supported': 500, 'not_verifiable_long': 255}. Median duration 52 s; 299 videos >= 300 s;
-mean chance 29.3%.
+Groups: {'perception': 210, 'temporal': 210, 'spatial_physical': 210, 'reasoning_knowledge': 210}. Largest sources: {'S-EMBER': 109, 'AoTBench': 92, 'ALLVB': 45, 'TOC-Bench': 38, 'UrbanVideo-Bench': 34, 'Camera Movement Understanding (BU_Google)': 33, 'VideoAds': 31, 'Video-MME-v2': 28}.
+Verification reasons: {'reversed_clip': 88, 'supported': 533, 'not_verifiable_long': 219}. Median duration 42 s; 282 videos >= 300 s;
+mean chance 29.7%.
 
 ## Licences
-Every item keeps the licence of its source benchmark (field `license`; {'unknown': 183, 'CC-BY-4.0': 62, '': 42, 'custom': 62, 'CC-BY-NC-SA-4.0': 141, 'MIT': 103, 'CC-BY-NC-4.0': 161, 'Apache-2.0': 78, 'CC-BY-SA-4.0': 7, 'CC-BY-NC-ND-4.0': 1}). Items are redistributed for
+Every item keeps the licence of its source benchmark (field `license`; {'unknown': 185, 'CC-BY-4.0': 57, '': 42, 'custom': 72, 'CC-BY-NC-SA-4.0': 137, 'MIT': 99, 'CC-BY-NC-4.0': 156, 'Apache-2.0': 84, 'CC-BY-SA-4.0': 7, 'CC-BY-NC-ND-4.0': 1}). Items are redistributed for
 research evaluation only; check the source benchmark's terms before any other use.