Microsoft has introduced Phi-4-Mini-Reasoning, a compact 3.8-billion-parameter model that achieves superior math reasoning performance compared to significantly larger competitors through a systematic four-step training recipe.

The methodology involves large-scale mid-training on distilled long-chain-of-thought data, supervised fine-tuning, Rollout DPO using curated preference datasets, and reinforcement learning with verifiable rewards.

On the Math-500 benchmark, Phi-4-Mini-Reasoning outperforms DeepSeek-R1-Distill-Qwen-7B by 3.2 points and DeepSeek-R1-Distill-Llama-8B by 7.7 points.

The results validate that a carefully designed training recipe with high-quality chain-of-thought data can unlock strong reasoning capabilities in resource-constrained small language models.