ConsistRM: Improving Generative Reward Models via Consistency-Aware Self-Training
Organizations: Baidu Inc., Beijing, China
Abstract
Generative reward models (GRMs) have emerged as a promising approach for aligning Large Language Models (LLMs) with human preferences by offering greater representational capacity and flexibility than traditional scalar reward models. However, GRMs face two major challenges: reliance on costly human-annotated data restricts scalability, and self-training approaches often suffer from instability and vulnerability to reward hacking. To address these issues, we propose ConsistRM, a self-training framework that enables effective and stable GRM training without human annotations. ConsistRM incorporates the Consistency-Aware Answer Reward, which produces reliable pseudo-labels with temporal consistency, thereby providing more stable model optimization. Moreover, the Consistency-Aware Critique Reward is introduced to assess semantic consistency across multiple critiques and allocates fine-grained and differentiated rewards. Experiments on five benchmark datasets across four base models demonstrate that ConsistRM outperforms vanilla Reinforcement Fine-Tuning (RFT) by an average of 1.5%. Further analysis shows that ConsistRM enhances output consistency and mitigates position bias caused by input order, highlighting the effectiveness of consistency-aware rewards in improving GRMs. Our implementation is available at https://github.com/yuliangCarmelo/ConsistRM.
Figures & tables
| ID System | GT | RewardBench | PPE Pref | RM-Bench | RMB | JudgeBench | Overall | |
| AVG | ( ) | |||||||
| Open Generative Reward Models | ||||||||
| 1 EvalPlanner-Llama-8B | ✓ | 83.0 | 54.3 | 68.1 | - | 30.2 | - | - |
| 2 J1-Llama-8B | ✓ | 85.7 | 59.8 | 73.4 | - | 42.0 | - | - |
| 3 DeepSeek-GRM-27B | ✓ | 88.5 | 67.2 | - | 70.3 | - | - | - |
| Implemented Existing Method | ||||||||
| System | RewardBench | PPE Pref | RM-Bench | RMB | JudgeBench | Avg | ( ) |
| ConsistRM | 85.6 | 67.7 | 78.3 | 79.1 | 56.9 | 73.5 | - |
| w/o CACR | 84.9 | 64.8 | 77.3 | 78.1 | 56.0 | 72.2 | -1.3 |
| w/o Online-State Consistency Preference | 85.5 | 64.1 | 78.6 | 76.7 | 56.7 | 72.3 | -1.2 |
| w/o Memory-Driven Consistency Preference | 84.3 | 63.1 | 75.4 | 74.2 | 54.8 | 70.4 | -3.2 |
| Foundation Model | Method | RewardBench | PPE Pref | RM-Bench | RMB | JudgeBench | Overall | |
| AVG | ( ) | |||||||
| Qwen3-4B | Vanilla RFT | 80.0 | 64.7 | 76.6 | 76.7 | 51.1 | 69.8 | - |
| ConsistRM | 80.3 | 65.1 | 76.8 | 76.5 | 56.1 | 71.0 | +1.2 | |
| Qwen3-8B | Vanilla RFT | 85.4 | 65.4 | 78.2 | 78.2 | 55.4 | 72.5 | - |
| ConsistRM | 85.6 | 67.7 | 79.2 | 79.2 | 55.9 | 73.5 | +1.0 | |
| Qwen3-14B | Vanilla RFT | 87.4 | 66.3 | 79.3 | 76.3 | 68.6 | 75.6 | - |
| System | RewardBench | JudgeBench | Overall | |
| AVG | ( ) | |||
| Various Critique Rweard | ||||
| ConsistRM | 80.3 | 56.1 | 68.2 | - |
| w/ CACR-Low | 81.2 | 50.6 | 65.8 | -2.4 |
| w/ DeepConf-Tail | 80.4 | 50.3 | 65.4 | -2.8 |
| w/ DeepConf-Low | 79.8 | 51.2 | 65.5 | -2.7 |
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
| Hyperparameter | Value |
| Training Epochs | 4 |
| Global Batch Size | 64 |
| Learning Rate | 1e-6 |
| Maximum Prompt Length | 4096 tokens |
| Maximum Generation Length | 1024 tokens |
| PPO Mini-Batch Size | 32 |
| Model | Number of Examples |
| Qwen3-4B | 13,236 |
| Qwen3-8B | 12,098 |
| Qwen3-14B | 10,340 |
| 0 steps | 80 steps | 160 steps | 240 steps | 320 steps | |
| Acc (%) | 80.25 | 83.45 | 87.31 | 88.25 | 91.50 |
| Model | CodePrefBench | |
| Qwen3-4B + RFT | 62.1 | – |
| Qwen3-4B + ConsistRM | 66.6 | +4.5 |
| Qwen3-8B + RFT | 69.7 | – |
| Qwen3-8B + ConsistRM | 72.1 | +2.4 |
| System | Reward Bench | PPE Pref | RM- Bench | RMB | Judge Bench | Avg |
| ConsistRM | 85.6 | 67.7 | 78.3 | 79.1 | 56.9 | 73.5 |
| w/ removal | 86.1 | 67.9 | 76.2 | 79.2 | 57.2 | 73.3 |
Reward Modeling
Reward modeling learns scores or rankings that capture human goals and task success, guiding AI selection, reinforcement learning, and alignment.
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