Skill-Aware Data Selection and Fine-Tuning for Data-Efficient Reasoning Distillation
Lechen Zhang, Yunxiang Zhang, Wei Hu, Lu Wang
TL;DR
The paper tackles data efficiency in distilling reasoning from large LLMs by proposing a skill-centric framework that (1) attributes problems to a hierarchical skill tree, (2) samples data adaptively by per-skill weakness using an inverse-accuracy distribution P(skill) = clip(acc_skill^{-1}, 0, $w_{max}$) / sum_{skill'} clip(acc_skill'^{-1}, 0, $w_{max}$) with $w_{max}=10^4$, and (3) trains with explicit skill chains embedded in training instances. Using only 1K examples from a 100K pool, the approach yields consistent gains over random SFT on Qwen3-4B and Qwen3-8B across five math benchmarks, and the gains are amplified when combining skill-based sampling with skill-aware training. The method generalizes across skill taxonomies and model families (e.g., DeepSeek-R1-Distill-Llama-8B) and can outperform existing data-selection methods like LIMO and s1 in this data-constrained setting. These results demonstrate that structured, skill-centric training can dramatically improve data efficiency and interpretability in reasoning distillation, enabling smaller models to acquire robust, decomposed reasoning abilities with limited curated data.
Abstract
Large reasoning models such as DeepSeek-R1 and their distilled variants achieve strong performance on complex reasoning tasks. Yet, distilling these models often demands large-scale data for supervised fine-tuning (SFT), motivating the pursuit of data-efficient training methods. To address this, we propose a skill-centric distillation framework that efficiently transfers reasoning ability to weaker models with two components: (1) Skill-based data selection, which prioritizes examples targeting the student model's weaker skills, and (2) Skill-aware fine-tuning, which encourages explicit skill decomposition during problem solving. With only 1,000 training examples selected from a 100K teacher-generated corpus, our method surpasses random SFT baselines by +1.6% on Qwen3-4B and +1.4% on Qwen3-8B across five mathematical reasoning benchmarks. Further analysis confirms that these gains concentrate on skills emphasized during training, highlighting the effectiveness of skill-centric training for efficient reasoning distillation.
