arXiv AI
Sep 7

What Matters in On-Policy Distillation? A Perspective on Data Efficiency and Data Selection

The paper investigates data efficiency and selection in On‑Policy Distillation (OPD) for large language models. It shows that 1‑shot OPD—training on a single example—consistently improves performance, especially when the example is hard, and that longer chain‑of‑thought (CoT) paths drive the gains rather than token entropy. Based on these findings, the authors propose a simple hard‑example selection strategy that, using only eight carefully chosen hard examples, matches the performance of a 17,000‑example baseline across models from 1.5B to 7B parameters.

By Zhinan Hou, Jiaqi Zhang, Xunliang Cai, Keyou You