Confidence Has a Timing Problem: What SFT, RL, and Distillation Change in Reasoning Models
TL;DR for operators A reasoning model can have useful confidence at one point in its workflow and misleading confidence at another. In a controlled comparison using the same Qwen2.5-7B-Instruct backbone and reasoning-data mixture, on-policy distillation produced the strongest average signal for estimating difficulty before reasoning, supervised fine-tuning supplied particularly useful confidence for stopping weak traces during generation, and reinforcement learning gained the most from confidence-based filtering after traces were complete.1 ...
