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arXiv 2505.22017cs.CL
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二次思考的代价:关于大语言模型推理效率的评估

The Price of a Second Thought: On the Evaluation of Reasoning Efficiency in Large Language Models

University of Electronic Science and Technology of China(电子科技大学);Beijing Academy of Artificial Intelligence(北京人工智能研究院);Nanyang Technological University(南洋理工大学)

Siqi Fan, Bowen Qin, Peng Han, Shuo Shang, Yequan Wang, Aixin Sun

AI总结:

针对大语言模型推理中的过度思考问题,提出COTHINK两阶段流水线,通过指令模型起草大纲、思考模型扩展,在保持准确率的同时减少21.1%的token使用。

摘要:

近期通过强化学习和反向检查思维链(backward-checking CoT)训练的思考模型常常存在过度思考的问题:即使在简单问题上也会产生过长的输出,浪费计算资源。现有的基于token效率的评估方法忽略了问题难度和中间计算成本,因此给出的视角并不全面。我们将推理效率形式化为思考模型与指令模型之间的相对度量,将指令模型视为最小努力基线。对四种思考模型和多个基准的系统性研究揭示了两个一致的规律:(i)指令模型在整体上实现了更高的效率;(ii)问题难度影响效率,思考模型在简单问题上浪费计算,但在较难问题上提供价值。基于这一洞察,我们提出了COTHINK,一个简单的两阶段流水线:指令模型起草简要大纲,思考模型对其进行扩展。在GSM8K、MATH500和AIME24上,COTHINK在保持四种思考模型准确率的同时,将token使用量减少了21.1%,并且与强效率基线相比仍具有竞争力。

英文摘要:

Recent thinking models trained with reinforcement learning and backward-checking CoT often suffer from overthinking: they produce excessively long outputs even on simple problems, wasting computation. Existing evaluations, based on token efficiency, give an incomplete view as they neglect problem difficulty and intermediate computation costs. We formalize reasoning efficiency as a relative measure between thinking and instruct models, treating instruct models as the minimal-effort baseline. A systematic study across four thinking models and multiple benchmarks reveals two consistent patterns: (i) instruct models achieve higher efficiency overall, and (ii) problem difficulty affects efficiency, with thinking models wasting computation on easy problems but providing value on harder ones. Building on this insight, we propose COTHINK, a simple two-stage pipeline: an instruct model drafts a brief outline, and a thinking model expands it. On GSM8K, MATH500, and AIME24, COTHINK cuts token usage by 21.1% while keeping accuracy on four thinking models, and remains competitive with strong efficiency baselines.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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