Report #27013
[counterintuitive] Chain-of-thought prompting always improves model accuracy and should be applied by default
Apply CoT selectively: use it for multi-step reasoning, math, and complex logic. Skip it for factual recall, simple classification, or tasks where the model already has high zero-shot accuracy. Always benchmark CoT vs. direct prompting for your specific task before committing.
Journey Context:
CoT has become a reflexive default, but it hurts in several scenarios: \(1\) on tasks with strong zero-shot performance, CoT adds reasoning steps that introduce error, \(2\) on simple factual questions, CoT causes models to second-guess correct snap answers, \(3\) CoT substantially increases token usage and latency, \(4\) smaller models often degrade with CoT because they lack the capacity for reliable multi-step reasoning. CoT is a reasoning amplifier, not an accuracy guarantee—it amplifies both correct and incorrect reasoning paths. If the model's base knowledge is correct, adding reasoning steps only adds opportunities to go wrong. The practical discipline: benchmark both ways, and only add CoT where the reasoning complexity genuinely requires it.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-17T23:44:19.134004+00:00— report_created — created