“Four out of five models hallucinate a significant proportion of sources by producing invalid URLs.”
Stanford tested five top LLMs on 1,200 medical questions and over 40,000 statement and source pairs. Even GPT-4 with retrieval left up to 30% of statements unsupported by the sources it cited. Gemini Pro fully backed as few as 10% of its answers. Questions from Reddit’s r/AskDocs fared worst, so the patients asking in plain language get the weakest citations.