AIMER: Calibration-Free Task-Agnostic MoE Expert Pruning

Zongfang Liu, Guangyi Chen, Yifan Shen, Shengkun Tang, Huan Wang, Xin Yuan


Abstract
Mixture-of-Experts (MoE) language models increase parameter capacity without proportional per-token computation, yet deployment still requires storing the full expert pool, making expert pruning important for reducing memory and serving overhead. Existing task-agnostic expert-pruning methods are typically calibration-dependent: they estimate expert importance from routing or activation statistics on a calibration set, making pruning decisions sensitive to calibration-data variation while introducing substantial preprocessing cost. We propose AIMER (Absolute mean over root mean square IMportance for Expert Ranking), a simple calibration-free criterion that identifies more distinct experts by capturing the concentration pattern of expert weights, making it well suited for task-agnostic expert pruning. Across 7B to 47B MoE language models with distinct architectures and 16 diverse benchmarks, AIMER consistently delivers stronger capability balance across diverse tasks than existing calibration-free methods. Surprisingly, AIMER also achieves better balance than strong calibration-based expert-pruning baselines calibrated on the widely used task-agnostic C4 corpus, while requiring only 0.22–2.06 seconds to score all experts.
Anthology ID:
2026.findings-emnlp.904
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
19145–19162
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.904/
DOI:
Bibkey:
Cite (ACL):
Zongfang Liu, Guangyi Chen, Yifan Shen, Shengkun Tang, Huan Wang, and Xin Yuan. 2026. AIMER: Calibration-Free Task-Agnostic MoE Expert Pruning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 19145–19162, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
AIMER: Calibration-Free Task-Agnostic MoE Expert Pruning (Liu et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.904.pdf