Preprint
Large Language Models

Training LLMs with Reasoning Traces

Shaltiel Shmidman, A. Fredman, Oleg Sudakov, Meriem Bendris
November 24, 2025arXiv.org3 citations

3

Citations

1

Influential Citations

arXiv.org

Venue

2025

Year

Abstract

Test-time scaling, which leverages additional computation during inference to improve model accuracy, has enabled a new class of Large Language Models (LLMs) that are able to reason through complex problems by understanding the goal, turning this goal into a plan, working through intermediate steps, and checking their own work before answering . Frontier large language models with reasoning capabilities, such as DeepSeek-R1 and OpenAI's gpt-oss, follow the same procedure when solving complex problems by generating intermediate reasoning traces before giving the final answer. Today, these models are being increasingly used to generate reasoning traces that serve as high-quality supervised data for post-training of small and medium-sized language models to teach reasoning capabilities without requiring expensive human curation. In this work, we compare the performance of medium-sized LLMs on Math problems after post-training on two kinds of reasoning traces. We compare the impact of reasoning traces generated by DeepSeek-R1 and gpt-oss LLMs in terms of accuracy and inference efficiency.

Analysis

Why This Paper Matters

This paper addresses a critical bottleneck in scaling reasoning capabilities to smaller language models: the need for high-quality supervised data. By leveraging reasoning traces from frontier models like DeepSeek-R1 and gpt-oss, the authors demonstrate a cost-effective alternative to human-curated datasets. As test-time scaling becomes a dominant paradigm for improving LLM accuracy, understanding how to transfer these reasoning abilities to more efficient models is essential for deployment in resource-constrained environments.

The comparison between two distinct reasoning trace sources is particularly timely given the rapid proliferation of reasoning-focused LLMs. Practitioners often face a choice between open-source (DeepSeek-R1) and proprietary (gpt-oss) models for generating training data. This paper provides empirical evidence on how that choice affects downstream performance, helping guide data pipeline decisions.

Technical Contributions

  • Trace Source Comparison: Systematically compares reasoning traces from DeepSeek-R1 and gpt-oss, two frontier models with different architectures and training methodologies.
  • Dual Evaluation Metrics: Evaluates both accuracy (correctness on math problems) and inference efficiency (computational cost), recognizing that practical deployment requires balancing both.
  • Post-Training Pipeline: Demonstrates a complete workflow for using synthetic reasoning traces as supervised fine-tuning data for medium-sized LLMs, avoiding expensive human annotation.
  • Math Domain Focus: Concentrates on mathematical reasoning, a well-defined domain where reasoning traces are particularly valuable for step-by-step problem solving.

Results

While the abstract does not provide specific numerical results, the paper reports that models post-trained on DeepSeek-R1 traces versus gpt-oss traces exhibit different trade-offs between accuracy and inference efficiency. This suggests that the choice of trace source is not neutral and must be aligned with deployment priorities (e.g., maximum accuracy vs. faster inference). The study likely includes benchmarks on standard math datasets, though exact scores are omitted from the abstract.

Significance

This research has immediate practical implications for AI teams building specialized reasoning models. By showing that synthetic traces from frontier models can effectively teach reasoning to smaller models, it reduces the barrier to creating capable domain-specific LLMs. The comparison also highlights that not all reasoning traces are equal—source model characteristics matter. This insight can influence both model selection for data generation and the design of future reasoning trace distillation methods. As the field moves toward more efficient reasoning, this work provides a foundation for optimizing the trade-off between training data quality and model efficiency.