In 2026, no single "hallucination rate" exists. Whether you use Vectara’s HHEM...

https://holdensinsightfulblogs.wordpress.com/2026/05/18/why-did-gpt-4o-accuracy-drop-to-64-4-when-the-user-believed-something-false/

In 2026, no single "hallucination rate" exists. Whether you use Vectara’s HHEM or AA-Omniscience depends on your needs. One model might show 5% error while another hits 20%. Given $67.4 billion in annual data losses, choosing the right benchmark is vital