LIMOPro: Reasoning Refinement for Efficient and Effective Test-time Scaling

Fuente: arXiv
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Main Authors: Xiao, Yang, Wang, Jiashuo, Yuan, Ruifeng, Xu, Chunpu, Xu, Kaishuai, Li, Wenjie, Liu, Pengfei
Format: Preprint
Published: 2025
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author Xiao, Yang
Wang, Jiashuo
Yuan, Ruifeng
Xu, Chunpu
Xu, Kaishuai
Li, Wenjie
Liu, Pengfei
author_facet Xiao, Yang
Wang, Jiashuo
Yuan, Ruifeng
Xu, Chunpu
Xu, Kaishuai
Li, Wenjie
Liu, Pengfei
contents Large language models (LLMs) have demonstrated remarkable reasoning capabilities through test-time scaling approaches, particularly when fine-tuned with chain-of-thought (CoT) data distilled from more powerful large reasoning models (LRMs). However, these reasoning chains often contain verbose elements that mirror human problem-solving, categorized as progressive reasoning (the essential solution development path) and functional elements (verification processes, alternative solution approaches, and error corrections). While progressive reasoning is crucial, the functional elements significantly increase computational demands during test-time inference. We introduce PIR (Perplexity-based Importance Refinement), a principled framework that quantitatively evaluates the importance of each reasoning step based on its impact on answer prediction confidence. PIR systematically identifies and selectively prunes only low-importance functional steps while preserving progressive reasoning components, creating optimized training data that maintains the integrity of the core solution path while reducing verbosity. Models fine-tuned on PIR-optimized data exhibit superior test-time scaling properties, generating more concise reasoning chains while achieving improved accuracy (+0.9\% to +6.6\%) with significantly reduced token usage (-3\% to -41\%) across challenging reasoning benchmarks (AIME, AMC, and GPQA Diamond). Our approach demonstrates strong generalizability across different model sizes, data sources, and token budgets, offering a practical solution for deploying reasoning-capable LLMs in scenarios where efficient test-time scaling, response time, and computational efficiency are valuable constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19187
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle LIMOPro: Reasoning Refinement for Efficient and Effective Test-time Scaling
Xiao, Yang
Wang, Jiashuo
Yuan, Ruifeng
Xu, Chunpu
Xu, Kaishuai
Li, Wenjie
Liu, Pengfei
Computation and Language
Artificial Intelligence
Large language models (LLMs) have demonstrated remarkable reasoning capabilities through test-time scaling approaches, particularly when fine-tuned with chain-of-thought (CoT) data distilled from more powerful large reasoning models (LRMs). However, these reasoning chains often contain verbose elements that mirror human problem-solving, categorized as progressive reasoning (the essential solution development path) and functional elements (verification processes, alternative solution approaches, and error corrections). While progressive reasoning is crucial, the functional elements significantly increase computational demands during test-time inference. We introduce PIR (Perplexity-based Importance Refinement), a principled framework that quantitatively evaluates the importance of each reasoning step based on its impact on answer prediction confidence. PIR systematically identifies and selectively prunes only low-importance functional steps while preserving progressive reasoning components, creating optimized training data that maintains the integrity of the core solution path while reducing verbosity. Models fine-tuned on PIR-optimized data exhibit superior test-time scaling properties, generating more concise reasoning chains while achieving improved accuracy (+0.9\% to +6.6\%) with significantly reduced token usage (-3\% to -41\%) across challenging reasoning benchmarks (AIME, AMC, and GPQA Diamond). Our approach demonstrates strong generalizability across different model sizes, data sources, and token budgets, offering a practical solution for deploying reasoning-capable LLMs in scenarios where efficient test-time scaling, response time, and computational efficiency are valuable constraints.
title LIMOPro: Reasoning Refinement for Efficient and Effective Test-time Scaling
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2505.19187