arXiv Computation and Language

A Strong MoE Is All You Need for Process Supervision

The paper demonstrates that expert routing statistics in Mixture-of-Experts (MoE) models can serve as an intrinsic process-confidence signal, rivaling conventional output-logit confidence. Leveraging this insight, the authors develop RoCo-Rethink, which selectively regenerates uncertain reasoning steps, and RoCo-PRM, which automatically annotates reasoning trajectories using routing-derived step scores and distills them into a standalone process reward model. Across various MoE architectures and reasoning tasks, both methods outperform strong baselines and transfer effectively between models and tasks.

arXiv AI
2d ago

Routes of Reasoning: Reading and Reshaping Test-Time Compute in MoE Models

The paper introduces a method to control reasoning behaviors in Mixture-of-Experts (MoE) language models by labeling sentence-level segments with six distinct reasoning behaviors (planning, execution, restatement, fact, reflection, and conclusion). Linear probes on MoE router logits can predict these behaviors nearly as accurately as probes on the full hidden state, enabling the authors to edit router scores during inference to reduce overthinking. This intervention cuts generated tokens by a median of 30.4% (up to 63.3%) across multiple models and benchmarks without significant loss in accuracy, and often improves it.

By Shengjie Wang, Mohsen Fayyaz, Nanyun Peng
arXiv Computation and Language
Sep 30

RAWR: Reward Assignment Without Rollouts in Verifiable Domains

arXiv:2603.17815v2 Announce Type: replace Abstract: Understanding and evaluating multi-step reasoning in LLMs at the level of individual steps remains a key challenge. Process reward models (PRMs) pr...

By Corentin Royer (International Business Machines), Anna Hedstr\"om (ETH AI Center), Debarun Bhattacharjya (Lirio), Gaetano Rossiello (International Business Machines), Andrea Giovannini (International Business Machines), Mennatallah El-Assady (Department of Computer Science, ETH Zurich)
arXiv Machine Learning
Oct 23

Route-and-Generate: KL-Regularized Router Improvement for Reasoning Routing in LLMs

Route-and-Generate (Rouge) is a hierarchical training framework that lets large language models decide how much reasoning to apply to each input. It separates reasoning effort from answer generation by using a routing policy that distributes a fixed sampling budget across different reasoning formats, while the base model is trained with GRPO and per-sample rewards. The method employs a rank‑based reward favoring shorter correct solutions and updates the router through a closed‑form KL‑regularized policy improvement, leading to more concise answers on easy tasks and longer reasoning on harder ones, thereby improving accuracy‑efficiency trade‑offs on multiple reasoning benchmarks.

By Tien-Phat Nguyen, Truong Nguyen, Thanh-Thien Le, Hoang Phan, Thien Huu Nguyen, Linh Ngo Van, Trung Le
arXiv AI
Oct 1

Learning Process Rewards via Reasoning State Propagation

The paper introduces Reasoning State Propagation (RSP), a method that models each reasoning prefix with a binary validity state and learns transitions between successive states. RSP predicts break and repair probabilities to connect intermediate reasoning states to the final outcome, enabling outcome supervision to guide learning of earlier steps. Experiments on reasoning search, response selection, and reinforcement learning show RSP consistently outperforms existing Process Reward Models, achieving notable gains over Qwen2.5-Math-PRM.

By Kai Gan, Zi-Hao Zhou, Bo Ye, Jian Zhao, Min-Ling Zhang, Tong Wei
arXiv Computation and Language
3d ago

Enhancing Language Model Reasoning with Structured Multi-Level Modeling

The paper introduces Multi-Level Reasoning (MLR), a two-level stochastic framework that separates long chain-of-thought generation into a high-level planner producing structured step descriptors and a low-level executor generating detailed reasoning. MLR replaces single-policy reinforcement learning with an iterative Step‑DPO preference optimization that uses Twisted Sequential Monte Carlo for scalable, stepwise supervision, improving training stability and accuracy. Experiments on math, science, and logic benchmarks show that MLR outperforms both supervised fine‑tuning and strong RL baselines while maintaining robustness over extended reasoning horizons.

By Siheng Xiong, Ali Payani, Faramarz Fekri