Are Many Tasks Necessary for General LLM Evaluation? A Matrix Completion View of Benchmark Redundancy

Kohei Tsuji, Yusuke Sakai, Hidetaka Kamigaito, Taro Watanabe


Abstract
Large language model (LLM) evaluation usually averages scores across many benchmark tasks, implicitly assuming broad task coverage is necessary for reliable general evaluation. This practice also implicitly treats all benchmark tasks as equally important for general evaluation. We revisit this assumption by treating benchmark results as a model-task score matrix under the performance prediction task. We find that a broad range of benchmarks are redundant with scores for 100 LLMs on 13 aggregate tasks and 523 subtasks. Specifically, we recovered model rankings with high rank correlation with the ALS matrix completion method after masking out several task scores. This means that no tasks dominated the recovery process, and both low-scoring and high-scoring tasks shared the same trends. Further analyses show that multiple-choice scores allow us to recover model rankings on free-form generation tasks. For general model ranking, free-form generation evaluation is not necessarily more informative than multiple-choice evaluation. These findings suggest that evaluating general-purpose LLMs can be accomplished with fewer tasks than the current common practice. Our analysis also estimates the number of models required to capture the overall trends in the benchmarks.
Anthology ID:
2026.aacl-long.55
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1172–1187
Language:
URL:
https://aclanthology.org/2026.aacl-long.55/
DOI:
Bibkey:
Cite (ACL):
Kohei Tsuji, Yusuke Sakai, Hidetaka Kamigaito, and Taro Watanabe. 2026. Are Many Tasks Necessary for General LLM Evaluation? A Matrix Completion View of Benchmark Redundancy. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 1172–1187, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Are Many Tasks Necessary for General LLM Evaluation? A Matrix Completion View of Benchmark Redundancy (Tsuji et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-long.55.pdf