Not Every Rubric Teaches Equally: Policy-Aware Rubric Rewards for RLVR

Hugging Face Daily Papers Papers

Summary

This paper introduces POW3R, a policy-aware rubric reward framework for reinforcement learning with verifiable rewards (RLVR). It shows that static rubric aggregation misallocates learning signal, and POW3R achieves faster convergence and better performance across multiple settings.

Reinforcement learning with verifiable rewards has made post-training highly effective when correctness can be checked automatically. However, many important model behaviors require satisfying several qualitative criteria at once. Rubric-based rewards address this setting by grading prompt-specific criteria and aggregating them into a scalar reward. Yet standard static aggregations conflate a criterion's human-assigned importance with its current usefulness as an optimization signal. We show that this assumption breaks down in rubric RL: many important criteria are already saturated or currently unreachable, while criteria that distinguish rollouts are not necessarily those with the largest human weights. We introduce POW3R, a policy-aware rubric reward framework that preserves human weights and category balance as the rubric objective while adapting criterion-level reward weights during training. POW3R uses rollout-level contrast to emphasize criteria that currently separate the policy's outputs, making the GRPO reward more informative without changing the underlying evaluation target. Across three base policies on two datasets spanning multimodal and text-only settings, POW3R wins 24 of 30 base-policy/metric comparisons, improving both mean rubric reward and strict completion (the fraction of prompts whose response satisfies every required rubric criterion) over vanilla GRPO with rubric rewards, and reaches the same plateau in 2.5--4times fewer training steps. Rubric rewards should therefore distinguish what should matter in the final answer from what can teach the current policy.
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Source: https://huggingface.co/papers/2605.20164 “Not Every Rubric Teaches Equally: Policy-Aware Rubric Rewards for RLVR”

As RL post-training expands beyond fully verifiable domains, rubrics, or checklists, are becoming a common reward interface for open-ended and multimodal tasks.

The question we study is: Should the same rubric weights that define final answer quality also determine what the current policy learns from during RL?

Our finding is no - A criterion can be important for the final response, but if all sampled rollouts pass it or all sampled rollouts fail it, it provides no group-relative learning signal. Across our multimodal setting and HealthBench, roughly half of rubric criteria are non-contrastive for a fresh policy, and static aggregation routes 45–51% of within-category training pressure to such criteria.

In this work, we: • diagnose how static rubric aggregation misallocates learning signal, • show that human importance and policy-dependent usefulness can decouple, and • introduce POW3R, a policy-aware rubric reward framework that preserves the evaluation target while adapting criterion-level reward weights during training.

Across three base policies and multimodal/text-only settings, POW3R wins 24/30 base-policy/metric comparisons and reaches the same plateau in 2.5–4× fewer training steps.

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