
This paper completely changed how I think about what a reasoning model should be rewarded for:
Sample solutions -> Label every step of the chain -> Train a PRM on the steps -> Score candidates step by step -> Select the best solution
Here is the 5-step blueprint:
Two schools of reward: an ORM looks only at the final result of the chain, while a PRM receives feedback on every intermediate reasoning step.
Step-level labeling: humans annotate individual solution steps, which pinpoints the exact location of an error instead of one correct-or-not signal over the whole output.
PRM as verifier: the trained model scores chains step by step and picks the best solution out of many generator samples.
Active learning: labeling targets the most informative chains rather than everything in order, which sharply raises the efficiency of expensive human feedback.
Alignment bonus: step-level reward directly encourages following a human-endorsed chain of thought, not just landing on a lucky result.
Key insight: rewarding the right answer teaches the model to reach it through wrong reasoning, so the process is what must be rewarded, not the result.
The process-supervised model solves 78% of problems on a representative subset of MATH.
Read this, then check the article below.

leanxbt@leanxbt
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