Large language models are often fine-tuned with rewards, but standard methods treat all tokens equally. On-Policy Self-Distillation (OPSD) improves this by having the model act as its own teacher to guide each token. However, the teacher's advice can be unreliable, causing training to plateau.
Teacher-Evolution Self-Distillation (TESD) lets the teacher generate its own outputs and score them on correctness and independence. These scores train the teacher to give better guidance and tell the student which advice to trust less. This two-way optimization boosts supervision quality.
TESD outperformed previous OPSD and reward-based methods across several tests. The finding underscores that strengthening the teacher's capability, not just the student's, is essential for continuous improvement. This opens a path to more efficient self-distillation without extra human data.
