Mentor-KD: Making Small Language Models Better Multi-step Reasoners
Authors: name: Hojae Lee, name: Junho Kim, name: SangKeun Lee

Large Language Models (LLMs) have displayed remarkable performances across
various complex tasks by leveraging Chain-of-Thought (CoT) prompting. Recently,
studies have proposed a Knowledge Distillation (KD) approach, reasoning
distillation, which transfers such reasoning ability of LLMs through
fine-tuning language models of multi-step rationales generated by LLM teachers.
However, they have inadequately considered two challenges regarding
insufficient distillation sets from the LLM teacher model, in terms of 1) data
quality and 2) soft label provision. In this paper, we propose Mentor-KD, which
effectively distills the multi-step reasoning capability of LLMs to smaller LMs
while addressing the aforementioned challenges. Specifically, we exploit a
mentor, intermediate-sized task-specific fine-tuned model, to augment
additional CoT annotations and provide soft labels for the student model during
reasoning distillation. We conduct extensive experiments and confirm
Mentor-KD's effectiveness across various models and complex reasoning tasks.