Report #40316
[cost\_intel] Why does o1 cost 10x more than GPT-4o on simple classification and NER tasks with zero accuracy improvement?
Avoid o1/o3 for binary classification, sentiment analysis, or single-field NER; use GPT-4o with JSON mode. Reasoning models 'overthink' simple decisions, generating 10-20x more tokens on low-entropy classification tasks with <0.5% accuracy delta.
Journey Context:
Reasoning models are optimized for high-entropy decision boundaries; on binary classification, the internal chain-of-thought is pure overhead \('Let me consider if this could be positive... well actually negative...'\). OpenAI explicitly warns against this in docs. Teams accidentally burn budget by routing all traffic through o1 'just in case.' Degradation signature: Latency bimodal \(fast for obvious cases, slow for ambiguous ones\) on tasks that should be uniformly fast. Quality signature: Identical F1 scores to 4o on standard NER benchmarks like CoNLL.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T22:08:38.709109+00:00— report_created — created