← Flash PapersRGSD: Rubric-Guided Self-Distillation
MohammadHossein Rezaei, Anas Mahmoud +7 more
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Medical domain avg improvement (RGSD):+6.1pp· RubricHub-medical + HealthBenchScience domain avg improvement (RGSD):+4.9pp· RubricHub-science + ResearchQAMedical domain avg improvement (GRPO):+5.9pp· RubricHub-medical + HealthBenchRubric-conditioning gap (Qwen-2.5-7B, medical):+45pp· RubricHub-medical training splitGRPO false-claim rate at step 450 (Qwen-2.5-7B medical):45.1%· HealthBench-300RGSD false-claim rate at step 450 (Qwen-2.5-7B medical):35.1%· HealthBench-300
Abstract

Rubrics have emerged as an alternative to RLVR in open-ended domains where a single ground-truth final answer is not available. Existing rubric-based training methods rely on an LLM verifier that scores each rollout against rubrics. This introduces substantial training-time overhead, exposes optimization to verifier-specific biases, and reduces rubric feedback to a sparse end-of-trajectory signal. We propose Rubric-Guided Self-Distillation (RGSD), a verifier-free training method in which the base policy, conditioned on the rubric, serves as the teacher for the unconditioned student. RGSD distills the rubric-conditioned teacher distribution into the student token-by-token, replacing sparse trajectory-level rewards with dense per-token learning signals and removing the LLM judge from the training loop entirely. Across Qwen-2.5 (3B, 7B) and Qwen3-Thinking (4B, 8B) models on medical and science domains, RGSD achieves rubric satisfaction comparable to judge-based GRPO while using one on-policy rollout per prompt and no training-time verifier calls. Ablations show that raw rubrics provide a stronger teacher enrichment signal than self-generated reference responses, while a stronger GRPO judge can outperform RGSD in some settings, positioning RGSD as a complementary verifier-free alternative when verifier cost or reliability is the bottleneck.

Concepts:GRPO