Do Benchmarks Measure the Same Thing? Evaluation-Free Benchmark Redundancy Analysis with SAE

Yaoning Wang, Jiahao Ying, Yubo Ma, Yu Wan, Dayiheng Liu, Yixin Cao, Yu-Gang Jiang


Abstract
The rapid growth of LLM evaluation resources makes exhaustive benchmark curation increasingly difficult. Existing efficient benchmarking methods reduce evaluation cost by selecting representative subsets or predicting full-benchmark performance, but typically require evaluation results from many models and additional training. In this paper, we ask a more fundamental question: to what extent do benchmarks actually measure different things? We study this question at two levels: intra-benchmark redundancy, which supports benchmark compression, and inter-benchmark similarity, which supports evaluation-suite design. We first formalize both notions through a functionalist behavioral criterion, and then propose an evaluation-free proxy based on Sparse Autoencoder (SAE) features for redundancy diagnosis. Our central hypothesis is that behavioral overlap can be approximated by feature overlap. This hypothesis yields level-specific metrics based on feature-coverage saturation within benchmarks and feature-footprint overlap across benchmarks. Experiments show that SAE feature-based redundancy strongly correlates with performance-based redundancy across 17 benchmarks, while SAE-guided subset selection produces more stable and representative subsets than random sampling. SAE feature overlap also predicts inter-benchmark performance similarity across 8 benchmarks. These results show that SAE features can turn benchmark analysis from a costly performance-matrix problem into a feature-footprint problem, enabling evaluation-free benchmark compression and suite curation.
Anthology ID:
2026.emnlp-main.1284
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
29255–29271
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1284/
DOI:
Bibkey:
Cite (ACL):
Yaoning Wang, Jiahao Ying, Yubo Ma, Yu Wan, Dayiheng Liu, Yixin Cao, and Yu-Gang Jiang. 2026. Do Benchmarks Measure the Same Thing? Evaluation-Free Benchmark Redundancy Analysis with SAE. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 29255–29271, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Do Benchmarks Measure the Same Thing? Evaluation-Free Benchmark Redundancy Analysis with SAE (Wang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1284.pdf