# Confidence-Gated Chain-of-Thought

Chain-of-thought prompting improves complex reasoning but spends extra computation even on simple queries. A Sheffield team tested "think only when unsure" gating across four training-free confidence signals, three model families and seven reasoning benchmarks, finding that effectiveness varies widely by model and task and tracing the variation to confidence-score saturation and a selection bias that sends the hardest queries to chain-of-thought. Their Pareto-optimal threshold selection reduces chain-of-thought usage by about 30% without sacrificing accuracy where the confidence signal is strong, and falls back toward full chain-of-thought where it is weak.

Chain-of-thought prompting improves complex reasoning but spends extra computation even on simple queries. A Sheffield team tested "think only when unsure" gating across four training-free confidence signals, three model families and seven reasoning benchmarks, finding that effectiveness varies widely by model and task and tracing the variation to confidence-score saturation and a selection bias that sends the hardest queries to chain-of-thought. Their Pareto-optimal threshold selection reduces chain-of-thought usage by about 30% without sacrificing accuracy where the confidence signal is strong, and falls back toward full chain-of-thought where it is weak.