Student-in-the-Loop Chain-of-Thought Distillation via Generation-Time Selection

Fuente: arXiv
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Main Authors: He, Chaoqun, Chen, Yingfa, Xiao, Chaojun, Han, Xu, Wen, Lijie
Format: Preprint
Published: 2026
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author He, Chaoqun
Chen, Yingfa
Xiao, Chaojun
Han, Xu
Wen, Lijie
author_facet He, Chaoqun
Chen, Yingfa
Xiao, Chaojun
Han, Xu
Wen, Lijie
contents Large reasoning models achieve strong performance on complex tasks through long chain-of-thought (CoT) trajectories, but directly transferring such reasoning processes to smaller models remains challenging. A key difficulty is that not all teacher-generated reasoning trajectories are suitable for student learning. Existing approaches typically rely on post-hoc filtering, selecting trajectories after full generation based on heuristic criteria. However, such methods cannot control the generation process itself and may still produce reasoning paths that lie outside the student's learning capacity. To address this limitation, we propose Gen-SSD (Generation-time Self-Selection Distillation), a student-in-the-loop framework that performs generation-time selection. Instead of passively consuming complete trajectories, the student evaluates candidate continuations during the teacher's sampling process, guiding the expansion of only learnable reasoning paths and enabling early pruning of unhelpful branches. Experiments on mathematical reasoning benchmarks demonstrate that Gen-SSD consistently outperforms standard knowledge distillation and recent baselines, with improvements of around 5.9 points over Standard KD and up to 4.7 points over other baselines. Further analysis shows that Gen-SSD produces more stable and learnable reasoning trajectories, highlighting the importance of incorporating supervision during generation for effective distillation.
format Preprint
id arxiv_https___arxiv_org_abs_2604_02819
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Student-in-the-Loop Chain-of-Thought Distillation via Generation-Time Selection
He, Chaoqun
Chen, Yingfa
Xiao, Chaojun
Han, Xu
Wen, Lijie
Computation and Language
Large reasoning models achieve strong performance on complex tasks through long chain-of-thought (CoT) trajectories, but directly transferring such reasoning processes to smaller models remains challenging. A key difficulty is that not all teacher-generated reasoning trajectories are suitable for student learning. Existing approaches typically rely on post-hoc filtering, selecting trajectories after full generation based on heuristic criteria. However, such methods cannot control the generation process itself and may still produce reasoning paths that lie outside the student's learning capacity. To address this limitation, we propose Gen-SSD (Generation-time Self-Selection Distillation), a student-in-the-loop framework that performs generation-time selection. Instead of passively consuming complete trajectories, the student evaluates candidate continuations during the teacher's sampling process, guiding the expansion of only learnable reasoning paths and enabling early pruning of unhelpful branches. Experiments on mathematical reasoning benchmarks demonstrate that Gen-SSD consistently outperforms standard knowledge distillation and recent baselines, with improvements of around 5.9 points over Standard KD and up to 4.7 points over other baselines. Further analysis shows that Gen-SSD produces more stable and learnable reasoning trajectories, highlighting the importance of incorporating supervision during generation for effective distillation.
title Student-in-the-Loop Chain-of-Thought Distillation via Generation-Time Selection
topic Computation and Language
url https://arxiv.org/abs/2604.02819