A verifiable reward is an objective training signal whose correctness is determined by a scoring procedure rather than a learned judgment. In reinforcement learning from verifiable rewards (RLVR), the procedure can assign a positive reward to a correct completion and 0 to an incorrect one, making a reward model optional. section 7.1
Verifiable rewards fit tasks with definitive outcomes, such as mathematics, coding, or theorem proving. They contrast with preference-based rewards: judging an explanation of opportunity cost requires assessments of clarity, completeness, and helpfulness, while checking a final mathematical answer can be deterministic. section 7.1 section 7.3.1
A practical verification pipeline typically needs:
- A task with a checkable target, such as a correct answer, executable program behavior, or proved statement. section 7.3.1
- An answer-extraction convention that isolates the result to be checked. section 7.1
- A verifier or scoring function that maps the extracted result to reward, often binary correctness. section 7.1
Checking a mathematical completion
For the sum of primes below 20, a completion may place 77 in a boxed final-answer field. A simple extraction rule reads that field; if the extracted answer equals 77, the verifier returns reward 1. The verifier evaluates the answer outcome, not whether every written reasoning step is stylistically preferred. section 7.1
RLVR uses policy-gradient training much like RLHF, but replaces a learned reward model with a verifier where possible. This reduces dependence on proxy preference signals for checkable tasks, while limiting direct applicability to domains where correctness can actually be scored objectively. section 6.6 section 7.1
Modern reasoning training applies this setup at scale on pretrained models. Earlier approaches used ground-truth signals, binary math rewards, code execution, and theorem verification; accessible tooling now includes TRL, Open Instruct, veRL, and OpenRLHF. section 7.2.1 section 7.3.1

