Process supervision and PRM800K establish step-level verification for math reasoning

Rather than rewarding only a final answer, the project collected human judgments on intermediate reasoning steps and trained process reward models from those labels. PRM800K exposes the annotations, labeling instructions and scored model samples used in the study.

What happened?

OpenAI reported that process supervision significantly outperformed outcome supervision for training reward models on MATH solutions; its process-supervised model solved 78% of a representative held-out MATH subset, and the project released PRM800K with 800,000 step-level correctness labels.

Why it matters

Step-level verification became a durable component of later mathematical reasoning systems, providing training and selection signals that diagnose where a chain of reasoning first goes wrong rather than judging only its endpoint.

Significance rationale: The work made step-level human feedback a concrete and scalable research object for mathematical reasoning, directly comparing process and outcome supervision and releasing PRM800K as a large process-supervision dataset that influenced later verifier and reward-model work.

Historical context

Primary evidence

Evidence & status at a glance

Significance
H2 · Field milestone
Verification
Paper released
Evidence level
E3 · Inspectable artifact
AI role
Substantive AI support
Formal assurance
Artifact available

How should these labels be read? →

Contribution & verification

Mathematical novelty
Tooling only
Interface
Informal, Symbolic, Numeric
AI contribution
Language models generated mathematical solution trajectories and learned reward models scored intermediate reasoning steps; the correctness labels used for process supervision were supplied by human annotators.
Human contribution
Researchers designed the process-versus-outcome supervision comparison, data-collection and active-learning procedures, while human labelers supplied step-level judgments for PRM800K.
Verification
Paper released · E3 · Inspectable artifact · Artifact available
Last reviewed
2026-09-11

Technical details

Systems
process-reward-model, prm800k
Organizations
openai
Problems
math-benchmark
Methods
process-supervision, process-reward-model, outcome-supervision, active-learning, verification

Sources & artifacts

Verification history

  • 2023-05-31 · Paper released · E2 · Research record

    OpenAI released the research paper and official description comparing process and outcome supervision on MATH.

  • 2023-05-31 · Paper released · E3 · Inspectable artifact

    The public PRM800K repository exposes 800,000 step-level labels, labeling instructions, data splits and evaluation samples. E3 records inspectability and does not imply independent verification of the reported model results.

Corrections

No corrections recorded.