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LongBench v2

LongBench v2 evaluates deep understanding and reasoning over long single documents, multiple documents, code repositories, dialogues, structured data, and in-context learning material.

LongBench v2 LongBench v2 paper v2 (2025-01-03)

Permanent entry
Task and data
LongBench v2 contains 503 multiple-choice questions over contexts ranging from 8,000 to two million words across six long-context task families.
Primary metric
Overall accuracy is reported in percent, with zero-shot and zero-shot chain-of-thought columns. Higher is better within the same column and truncation policy.
What it measures
deep understanding and reasoning over long single documents, multiple documents, code repositories, dialogues, structured data, and in-context learning material.
Comparison rules
Attach zero-shot versus chain-of-thought, model snapshot, context/truncation policy, and compensation rule. LongBench v1 and v2 are different datasets.
Access and licensing
The Compendium cites aggregate paper results only and does not reproduce long documents, questions, structured data, or answer choices.
Selected published third-party results for LongBench v2 LongBench v2 paper v2 (2025-01-03). Draconitic did not run these evaluations.
Published subjectScoreMetricSplit and evaluation settingSource record
o1-preview-2024-09-12longbench-v2:full:cot:uncompensated 57.7%higher, percent overall accuracyhistorical paper result 503-item full setZero-shot chain-of-thought; middle truncation beyond model context; invalid choices counted incorrect in the main table.The paper's compensated table uses another scoring treatment and must not be mixed with this row. LongBench v2 authorsPublished 2025-01-03, reviewed 2026-07-13original-paper, published-third-party
GPT-4o-2024-08-06longbench-v2:full:zero-shot:uncompensated 50.1%higher, percent overall accuracyhistorical paper result 503-item full setZero-shot column; middle truncation beyond model context; invalid choices counted incorrect in the main table.The adjacent CoT score is 51.2%; this anchor is specifically the zero-shot column. LongBench v2 authorsPublished 2025-01-03, reviewed 2026-07-13original-paper, published-third-party
Human expertslongbench-v2:full:human-15-minute 53.7%higher, percent overall accuracyhistorical human baseline 503-item full setExperts had a 15-minute time limit per item and could answer 'I don't know'; this occurred for eight percent of data.Time limits and recruited expertise define this baseline; it is not an unrestricted human ceiling. LongBench v2 authorsPublished 2025-01-03, reviewed 2026-07-13human-baseline, published-third-party

Claims and evidence

Claim ledger, 2