# When Should LLMs Verify Instead of Think Longer? > Source: > Published: 2026-06-19 05:02:43+00:00 Excited to share our paper: **Think Again or Think Longer? Selective Verification for Budget-Aware Reasoning** We introduce **SEVRA**, a serving-layer controller that decides when a frozen reasoning model should keep its first answer and when it should run active verification. The main finding is simple but important: **verification is useful, but not always worth the extra compute.** On MATH500, selective verification improves over always verifying while reducing harmful answer flips and verification tokens. On GSM8K, it verifies only a small fraction of examples but still improves accuracy. However, a longer initial solve can sometimes match the same accuracy with fewer total tokens. So our practical takeaway is: **Tune the initial reasoning budget first; then use selective verification when explicit checks, bounded retries, auditability, or regression-risk control matter.** A few questions we would love feedback on: When should a reasoning system verify instead of simply thinking longer? Should harmful answer flips be reported more often in test-time compute papers? Are cheap serving signals like token count and completion status enough for routing, or do we need learned controllers? What is the best way to evaluate test-time reasoning policies beyond accuracy and token cost? Paper: [Paper page - Think Again or Think Longer? Selective Verification for Budget-Aware Reasoning](https://huggingface.co/papers/2606.19808) Code: [GitHub - Sajib-006/SEVRA: Selective verification for budget-aware LLM reasoning, with reusable routing, gate training, and policy evaluation. ยท GitHub](https://github.com/Sajib-006/SEVRA) Feedback and discussion are very welcome.