Synthetic Data RL: Task Definition Is All You Need
Authors: name: Yiduo Guo, name: Zhen Guo, name: Chuanwei Huang, name: Zi-Ang Wang, name: Zekai Zhang, name: Haofei Yu, name: Huishuai Zhang, name: Yikang Shen

Reinforcement learning (RL) is a powerful way to adapt foundation models to
specialized tasks, but its reliance on large-scale human-labeled data limits
broad adoption. We introduce Synthetic Data RL, a simple and general framework
that reinforcement fine-tunes models using only synthetic data generated from a
task definition. Our method first generates question and answer pairs from the
task definition and retrieved documents, then adapts the difficulty of the
question based on model solvability, and selects questions using the average
pass rate of the model across samples for RL training. On Qwen-2.5-7B, our
method achieves a 29.2% absolute improvement over the base model on GSM8K (+2.9
pp vs. instruction-tuned, +6.6 pp vs. Self-Instruct), 8.7% on MATH, 13.1% on
GPQA (+7.0 pp vs. SynthLLM), 8.9% on MedQA, 17.7% on CQA (law) and 13.7% on CFA
(finance). It surpasses supervised fine-tuning under the same data budget and
nearly matches RL with full human data across datasets (e.g., +17.2 pp on
GSM8K). Adding 100 human demonstrations improves the performance of GSM8K only
by 0.4 pp, showing a limited added value. By reducing human data annotation,
Synthetic Data RL enables scalable and efficient RL-based model adaptation.
Code and demos are available at https://github.com/gydpku/Data_Synthesis_RL/.