arXiv AI

OBC-Prune: Outcome-Based Calibration for Large Reasoning Model Pruning

OBC‑Prune introduces an outcome‑based calibration approach for pruning large reasoning models, focusing on the causal importance of each reasoning sentence rather than uniform activation salience. By pairing correct and incorrect rollouts and using intervention‑based analysis, it assigns per‑token weights that guide one‑shot pruning methods such as SparseGPT, Wanda, and ALPS. Experiments on DeepSeek‑R1‑Distill‑Qwen models show consistent accuracy gains and shorter reasoning traces across multiple benchmarks at 40‑50% sparsity.

arXiv AI
6d ago

Improving the Chain-of-Thought Compressibility of Pruned Reasoning Models via Long--Short Contrastive Pruning

The paper introduces Contrastive Set-Difference (CSD), a pruning method that targets neurons involved in redundant reasoning by contrasting activations on long versus short correct solutions. CSD is combined with an extended preference-based chain-of-thought compression that also considers problems a pruned model always or never solves. Applied to a 7B model, the approach reduces thinking tokens by 8–22% on math benchmarks while maintaining accuracy within 0.5 points compared to traditional pruning and compression pipelines.

By Tao Jing, Chen Kang, Feifei Zhai, Pengyuan Liu, Dong Yu
arXiv Computation and Language
5d ago

Pruning via Causal Attribution Preserves Reasoning Performance in Large Language Models

The paper introduces Causal Attribution Pruning (CAP), a training‑free technique that identifies critical attention heads in large language models by measuring their causal impact on reasoning tasks. CAP estimates performance loss when each head is masked on a small calibration set, then translates these causal scores into weight‑level importance for pruning. Compared to magnitude‑only or activation‑based methods, CAP achieves up to 61% relative accuracy gains over Wanda on ARC‑Challenge at 20% sparsity and improves performance on GSM8K, StrategyQA, and ARC‑Challenge across Llama‑3‑8B‑Instruct and Mistral‑7B‑Instruct at 10%, 20%, and 50% sparsity.

By Amogh Sheth, Andrew Lin, Biruk Assefa, Yi Wen Huang, Yuhao Ge
arXiv AI
Jun 30

Beyond Scaling Law: A Data-Efficient Distillation Framework for Reasoning

arXiv:2508. 09883v2 Announce Type: replace-cross Abstract: Large language models (LLMs) demonstrate remarkable reasoning capabilities in tasks such as algorithmic coding and mathematical problem-solving.

By Xiaojun Wu, Xiaoguang Jiang, Huiyang Li, Jucai Zhai, Dengfeng Liu, Qiaobo Hao, Huang Liu, Zhiguo Yang, Ji Xie, Ninglun Gu, Jin Yang, Kailai Zhang, Yelun Bao, Jun Wang
arXiv AI
Jun 30

Reconsidering Overthinking: Penalizing Internal and External Redundancy in CoT Reasoning

arXiv:2508. 02178v3 Announce Type: replace Abstract: Large reasoning models (LRMs) often exhibit overthinking, producing verbose Chain-of-Thought (CoT) traces that increase inference cost and obscure the underlying reasoning process.

By Taihang Zhen, Jialiang Hong, Kai Chen, Guang Yang, Junlan Feng, Wenpeng Zhu, Jing Huo, Yang Gao, Depeng Wang, Haitao Wan, Xi Yang, Fanyu Meng, Yuyao Zhang, Ji Qi, Xiangyu Zhou
arXiv AI
Aug 25

Revisiting the Effectiveness of LLM Pruning for Test-Time Scaling

The paper revisits the impact of pruning on large language models (LLMs) during test-time scaling (TTS). While prior work found that structured pruning degrades reasoning performance, this study shows that unstructured pruning—removing only specific redundant weights—can actually improve TTS performance on reasoning benchmarks for models s1.1-7B and Qwen3-8B, sometimes surpassing the full-weight models. The authors also examine how different layer-wise sparsity allocation strategies affect these outcomes.

By Ocean Monjur, Shahriar Kabir Nahin, Anshuman Chhabra