Why?
ChatGPT sometimes makes stuff up; the official AI term for this is hallucination. ChatGPT sometimes hallucinates because these systems are probabilistic (which incorporate randomness), not deterministic (information that is known to be true and accurate because it is supplied by people directly or is personally identifiable).
Which Models are Less Prone to Hallucinations?
GPT-4 (the more capable model behind ChatGPT Plus and Microsoft Copilot) has improved and is less prone to hallucination. According to OpenAI, it's "40% more likely to produce factual responses than GPT-3.5 on our internal evaluations." But it's still not perfect. So verification of the output is still needed.
ChatGPT Often Makes up Fictional Sources
One area where ChatGPT usually gives fictional answers is when asked to create a list of sources. See the Twitter thread, "Why does chatGPT make up fake academic papers?" for a useful explanation of why this happens. Have you experienced this? Check out this FAQ: I can’t find the citations that ChatGPT gave me. What should I do?
Making These Models More Truthful
There is progress in making these systems more truthful by grounding them in external sources of knowledge. Some examples are Microsoft Copilot and Perplexity AI, which use internet search results to ground answers. However, the Internet sources used could also contain misinformation or disinformation. But at least with Copilot and Perplexity you can link to the sources used to begin verification.
Scholarly Sources as Grounding
There are also systems that combine language models with scholarly sources. For example:
A search engine that uses AI to search for and surface claims made in peer-reviewed research papers. Ask a plain English research question, and get word-for-word quotes from research papers related to your question. The source material used in Consensus comes from the Semantic Scholar database, which includes over 200M papers across all domains of science.
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