The openai/gpt-5-nano-2025-08-07 model achieved a hallucination rate of 10.5%, a factual consistency rate of 89.5%, an answer rate of 100.0%, and an average summary length of 105.7 words as of March 20, 2026.

Authors

• Person: Not available Organization: Vectara
  vectara/hallucination-leaderboard - GitHub

Sources

• vectara/hallucination-leaderboard - GitHub github.com Vectara via serper

Referenced by nodes (4)

• hallucination rate concept
• answer rate concept
• factual consistency rate concept
• average summary length concept