Beyond Verifiable Rewards: Scaling Reinforcement Learning for Language Models to Unverifiable Data

Fuente: arXiv
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Auteurs principaux: Tang, Yunhao, Wang, Sid, Madaan, Lovish, Munos, Rémi
Format: Preprint
Publié: 2025
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author Tang, Yunhao
Wang, Sid
Madaan, Lovish
Munos, Rémi
author_facet Tang, Yunhao
Wang, Sid
Madaan, Lovish
Munos, Rémi
contents We propose to scale RL to unverifiable data with a novel algorithm JEPO (Jensen's Evidence lower bound Policy Optimization). While most prior efforts on scaling RL for LLMs focus on verifiable data where ground truth answers are typically short-form and can be matched easily; we investigate the case where such assumptions are less valid (e.g., when answers are long-form such as mathematical proofs). To scale RL training to unverifiable data with contemporary training constraints, we propose JEPO. JEPO applies Jensen's evidence lower bound, a pragmatic simplification of the evidence lower bound which views chain-of-thought as a latent variable in the generative process. We show that on verifiable data (math), JEPO is as effective as RL with verifiable rewards; on semi-verifiable data (numina), JEPO improves on soft-match based evaluations compared to RL with verifiable rewards which can only leverage a subset of the data source; finally, on unverifiable data (numina-proof), JEPO outperforms SFT and a few ablation baselines on likelihood evaluations.
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id arxiv_https___arxiv_org_abs_2503_19618
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Beyond Verifiable Rewards: Scaling Reinforcement Learning for Language Models to Unverifiable Data
Tang, Yunhao
Wang, Sid
Madaan, Lovish
Munos, Rémi
Machine Learning
We propose to scale RL to unverifiable data with a novel algorithm JEPO (Jensen's Evidence lower bound Policy Optimization). While most prior efforts on scaling RL for LLMs focus on verifiable data where ground truth answers are typically short-form and can be matched easily; we investigate the case where such assumptions are less valid (e.g., when answers are long-form such as mathematical proofs). To scale RL training to unverifiable data with contemporary training constraints, we propose JEPO. JEPO applies Jensen's evidence lower bound, a pragmatic simplification of the evidence lower bound which views chain-of-thought as a latent variable in the generative process. We show that on verifiable data (math), JEPO is as effective as RL with verifiable rewards; on semi-verifiable data (numina), JEPO improves on soft-match based evaluations compared to RL with verifiable rewards which can only leverage a subset of the data source; finally, on unverifiable data (numina-proof), JEPO outperforms SFT and a few ablation baselines on likelihood evaluations.
title Beyond Verifiable Rewards: Scaling Reinforcement Learning for Language Models to Unverifiable Data
topic Machine Learning
url https://arxiv.org/abs/2503.19618