Vectara publishes AI hallucination leaderboard ranking chatbots, with ChatGPT exhibiting the least hallucination and Palm-Chat performing poorly. AI hallucinations, where chatbots invent information, are concerning for applications in law, health, and defense. GPT-4 achieves the lowest hallucination rate and highest accuracy, while Palm-Chat's responses are heavily littered with hallucinatory debris. *OpenAI is still killing it in this AI game.