Improve Mathematical Reasoning in Language Models by Automated Process Supervision
Written for the Research library (claude-opus-5-5) from the paper text. Original — arxiv.org/pdf/2406.06592
Summary
Process Reward Models (PRMs) score each intermediate step of a solution. On multi-step math they help LLMs more than verifiers that judge only the final answer. The catch is the step-level labels PRMs need. Until now these came from paid human annotators or from brute-force Monte Carlo rollouts launched at every step, and both are costly to scale. The Google DeepMind authors propose OmegaPRM, a divide-and-conquer Monte Carlo Tree Search procedure. It uses binary search to find the first faulty step in a chain-of-thought, reuses rollouts across tree nodes, and keeps correct and incorrect examples in balance. Its only input is questions paired with reference answers. From these it produced more than 1.5 million step-level annotations with no human labelling. The authors trained a PRM on this data and paired it with weighted self-consistency decoding. This raised instruction-tuned Gemini Pro from 51% to 69.4% on MATH500 and Gemma2 27B from 42.3% to 58.2%. The results suggest that cheap, fully automatic process supervision can outperform human-labelled resources such as PRM800K. That makes step-level reward modelling much more practical.
Key points
- Efficiency: With the same compute budget, the brute-force per-step method (as in Math-Shepherd and MiPS) produced about 200K data points, while OmegaPRM produced 15M, roughly 75 times more. The 15M were randomly downsampled to 1.5M for PRM training.
- GSM8K gains: Gemini Pro improved from 86.4% to 93.6% and Gemma2 27B from 74.0% to 92.2%. As the number of samples grew, competing PRMs drifted toward plain majority-vote accuracy, while the OmegaPRM-trained PRM kept a clear lead.
- Training objective: Pointwise soft labels gave the best per-step classification accuracy (70.1%), ahead of pairwise loss (64.2%) and pointwise hard labels (63.3%).
- Step splitting: Any run of consecutive tokens can count as a step, so there is no rule-based newline splitting. The search targets about 16 segments per solution, and the resulting step lengths look similar to those in PRM800K and Math-Shepherd.
- Limitations: The automatic labels contain noise (false positives and false negatives). The method also needs question–answer pairs with known correct answers, so it does not yet work for open-ended tasks.
Cited by
- Phi-4 Technical Report
- Do NOT Think That Much for 2+3=? On the Overthinking of o1-Like LLMs
- Towards Reasoning Era: A Survey of Long Chain-of-Thought for Reasoning Large Language Models
- Cognitive Behaviors that Enable Self-Improving Reasoners, or, Four Habits of Highly Effective STaRs
- rStar-Math: Small LLMs Can Master Math Reasoning with Self-Evolved Deep Thinking
- InternVL3.5: Advancing Open-Source Multimodal Models in Versatility, Reasoning, and Efficiency
- Generative Verifiers: Reward Modeling as Next-Token Prediction
- The Lessons of Developing Process Reward Models in Mathematical Reasoning
- ProcessBench: Identifying Process Errors in Mathematical Reasoning
- InternVL3: Exploring Advanced Training and Test-Time Recipes for Open-Source Multimodal Models
Cite
@misc{luo2024improve,
title = {{Improve Mathematical Reasoning in Language Models by Automated Process Supervision}},
author = {Luo, Liangchen and Liu, Yinxiao and Liu, Rosanne and Phatale, Samrat and Guo, Meiqi and Lara, Harsh and Li, Yunxuan and Shu, Lei and Zhu, Yun and Meng, Lei and Sun, Jiao and Rastogi, Abhinav},
year = {2024},
doi = {10.48550/arxiv.2406.06592},
eprint = {2406.06592},
archivePrefix = {arXiv},
url = {https://doi.org/10.48550/arxiv.2406.06592}
}References
- P. Christiano, J. Leike, T. B. Brown, M. Martic, S. Legg, and D. Amodei. Deep reinforcement learning from human preferences. arXiv preprint arXiv:1706.03741, 2017. find
- K. Cobbe, V. Kosaraju, M. Bavarian, M. Chen, H. Jun, L. Kaiser, M. Plappert, J. Tworek, J. Hilton, R. Nakano, C. Hesse, and J. Schulman. Training verifiers to solve math word problems. arXiv preprint arXiv:2110.14168, 2021. find our card
- X. Feng, Z. Wan, M. Wen, S. M. McAleer, Y. Wen, W. Zhang, and J. Wang. Alphazero-like tree-search can guide large language model decoding and training. arXiv preprint arXiv:2309.17179, 2023. find
- X. Feng, Z. Wan, M. Wen, S. M. McAleer, Y. Wen, W. Zhang, and J. Wang. Alphazero-like tree-search can guide large language model decoding and training. arXiv preprint arXiv:2309.17179, 2024. find
- Y. Fu, H. Peng, A. Sabharwal, P. Clark, and T. Khot. Complexity-based prompting for multi-step reasoning. In Proceedings of the 11th International Conference on Learning Representations (ICLR), May 2023. find our card
- Gemini Team, M. Reid, N. Savinov, D. Teplyashin, Dmitry, Lepikhin, T. Lillicrap, J. baptiste Alayrac, R. Soricut, A. Lazaridou, O. Firat, J. Schrittwieser, I. Antonoglou, R. Anil, S. Borgeaud, A. Dai, K. Millican, E. Dyer, M. Glaese, T. Sottiaux, B. Lee, F. Viola, M. Reynolds, Y. Xu, J. Molloy, J. C… find our card
- Gemma Team, M. Riviere, S. Pathak, P. G. Sessa, C. Hardin, S. Bhupatiraju, L. Hussenot, T. Mesnard, B. Shahriari, A. Ramé, J. Ferret, P. Liu, P. Tafti, A. Friesen, M. Casbon, S. Ramos, R. Kumar, C. L. Lan, S. Jerome, A. Tsitsulin, N. Vieillard, P. Stanczyk, S. Girgin, N. Momchev, M. Hoffman, S. Thak… find
- S. Hao, Y. Gu, H. Ma, J. J. Hong, Z. Wang, D. Z. Wang, and Z. Hu. Reasoning with language model is planning with world model. arXiv preprint arXiv:2305.14992, 2023. find
- D. Hendrycks, C. Burns, S. Kadavath, A. Arora, S. Basart, E. Tang, D. Song, and J. Steinhardt. Measuring mathematical problem solving with the math dataset. NeurIPS, 2021. find our card
- J. Huang, S. S. Gu, L. Hou, Y. Wu, X. Wang, H. Yu, and J. Han. Large language models can self-improve. arXiv preprint arXiv:2210.11610, 2022. find our card
- J. Kang, X. Z. Li, X. Chen, A. Kazemi, Q. Sun, B. Chen, D. Li, X. He, Q. He, F. Wen, J. Hao, and J. Yao. Mindstar: Enhancing math reasoning in pre-trained llms at inference time. arXiv preprint arXiv:2405.16265, 2024. — [arXiv:2405.16265](https://arxiv.org/abs/2405.16265) find
- Y. Li, Z. Lin, S. Zhang, Q. Fu, B. Chen, J.-G. Lou, and W. Chen. Making large language models better reasoners with step-aware verifier. arXiv preprint arXiv:2206.02336, 2023. — [arXiv:2206.02336](https://arxiv.org/abs/2206.02336) find
- H. Lightman, V. Kosaraju, Y. Burda, H. Edwards, B. Baker, T. Lee, J. Leike, J. Schulman, I. Sutskever, and K. Cobbe. Let’s verify step by step. arXiv preprint arXiv:2305.20050, 2023. find our card
- H. Liu, Y. Zhang, Y. Luo, and A. C.-C. Yao. Augmenting math word problems via iterative question composing. arXiv preprint arXiv:2401.09003, 2024. find
- L. Luo, Z. Lin, Y. Liu, L. Shu, Y. Zhu, J. Shang, and L. Meng. Critique ability of large language models. arXiv preprint arXiv:2310.04815, 2023. find
- Q. Ma, H. Zhou, T. Liu, J. Yuan, P. Liu, Y. You, and H. Yang. Let’s reward step by step: Step-level reward model as the navigators for reasoning. arXiv preprint arXiv:2310.10080, 2023. find
- OpenAI. GPT-4 technical report. arXiv preprint arXiv:2303.08774, 2023. find our card
- L. Ouyang, J. Wu, X. Jiang, D. Almeida, C. L. Wainwright, P. Mishkin, C. Zhang, S. Agarwal, K. Slama, A. Ray, J. Schulman, J. Hilton, F. Kelton, L. Miller, M. Simens, A. Askell, P. Welinder, P. Christiano, J. Leike, and R. Lowe. Training language models to follow instructions with human feedback. ar… find
- E. Perez, D. Kiela, and K. Cho. True few-shot learning with language models. arXiv preprint arXiv:2105.11447, 2021. find our card
- C. D. Rosin. Multi-armed bandits with episode context. Annals of Mathematics and Artificial Intelligence, 61(3):203–230, 2011. find
- D. Silver, A. Huang, C. J. Maddison, A. Guez, L. Sifre, G. van den Driessche, J. Schrittwieser, I. Antonoglou, V. Panneershelvam, M. Lanctot, S. Dieleman, D. Grewe, J. Nham, N. Kalchbrenner, I. Sutskever, T. Lillicrap, M. Leach, K. Kavukcuoglu, T. Graepel, and D. Hassabis. Mastering the game of go w… find
- D. Silver, J. Schrittwieser, K. Simonyan, I. Antonoglou, A. Huang, A. Guez, T. Hubert, L. Baker, M. Lai, A. Bolton, Y. Chen, T. Lillicrap, F. Hui, L. Sifre, G. van den Driessche, T. Graepel, and D. Hassabis. Mastering the game of go without human knowledge. nature, 550(7676):354–359, 2017. find
- Y. Tian, B. Peng, L. Song, L. Jin, D. Yu, H. Mi, and D. Yu. Toward self-improvement of llms via imagination, searching, and criticizing. arXiv preprint arXiv:2404.12253, 2024. find
- H. Touvron, L. Martin, K. Stone, P. Albert, A. Almahairi, Y. Babaei, N. Bashlykov, S. Batra, P. Bhargava, S. Bhosale, D. Bikel, L. Blecher, C. C. Ferrer, M. Chen, G. Cucurull, D. Esiobu, J. Fernandes, J. Fu, W. Fu, B. Fuller, C. Gao, V. Goswami, N. Goyal, A. Hartshorn, S. Hosseini, R. Hou, H. Inan,… find
- J. Uesato, N. Kushman, R. Kumar, F. Song, N. Siegel, L. Wang, A. Creswell, G. Irving, and I. Higgins. Solving math word problems with process-and outcome-based feedback. arXiv preprint arXiv:2211.14275, 2022. find our card
- P. Wang, L. Li, Z. Shao, R. X. Xu, D. Dai, Y. Li, D. Chen, Y. Wu, and Z. Sui. Math-Shepherd: Verify and reinforce LLMs step-by-step without human annotations. arXiv preprint arXiv:2312.08935, 2024a. find our card
- X. Wang, J. Wei, D. Schuurmans, Q. Le, E. Chi, S. Narang, A. Chowdhery, and D. Zhou. Self-consistency improves chain of thought reasoning in language models. In Proceedings of the 11th International Conference on Learning Representations (ICLR), May 2023. find our card
- Z. Wang, Y. Li, Y. Wu, L. Luo, L. Hou, H. Yu, and J. Shang. Multi-step problem solving through a verifier: An empirical analysis on model-induced process supervision. arXiv preprint arXiv:2402.02658, 2024b. find
- J. Wei, Y. Tay, R. Bommasani, C. Raffel, B. Zoph, S. Borgeaud, D. Yogatama, M. Bosma, D. Zhou, D. Metzler, E. H. Chi, T. Hashimoto, O. Vinyals, P. Liang, J. Dean, and W. Fedus. Emergent abilities of large language models, 2022a. find our card
- J. Wei, X. Wang, D. Schuurmans, M. Bosma, F. Xia, E. Chi, Q. V. Le, and D. Zhou. Chain-of-thought prompting elicits reasoning in large language models. In Proceedings of the 36th Conference on Neural Information Processing Systems (NeurIPS), Dec 2022b. find our card
- S. Yao, D. Yu, J. Zhao, I. Shafran, T. L. Griffiths, Y. Cao, and K. Narasimhan. Tree of thoughts: Deliberate problem solving with large language models. arXiv preprint arXiv:2305.10601, 2023. find
- F. Yu, A. Gao, and B. Wang. Ovm, outcome-supervised value models for planning in mathematical reasoning. arXiv preprint arXiv:2311.09724, 2024. find
- L. Yu, W. Jiang, H. Shi, J. Yu, Z. Liu, Y. Zhang, J. T. Kwok, Z. Li, A. Weller, and W. Liu. MetaMath: Bootstrap your own mathematical questions for large language models. arXiv preprint arXiv:2309.12284, 2023. find our card
- D. Zhang, S. Zhoubian, Z. Hu, Y. Yue, Y. Dong, and J. Tang. Rest-mcts*: Llm self-training via process reward guided tree search. arXiv preprint arXiv:2406.03816, 2024. find our card
- M. Świechowski, K. Godlewski, B. Sawicki, and J. Mańdziuk. Monte carlo tree search: A review of recent modifications and applications. arXiv preprint arXiv:2103.04931, 2021. — [arXiv:2103.04931](https://arxiv.org/abs/2103.04931) find