119a | Danger - Deep Research Hallucinates, Too!
Wait… Deep Research Hallucinates?
If you thought Deep Research tools were immune to the hallucination problem that plagues AI chatbots, think again! After spending more time using and reading reviews of Perplexity Deep Research—and comparing it with ChatGPT and Gemini’s offerings—I realized I need to be much clearer than I was in my last article.
These tools don’t just pull information from reliable sources; they sometimes make things up.
Perplexity: Slick, Fast… and Wrong?
Yes, Perplexity is fast, free, and delivers a well-structured report that looks authoritative. But here’s the catch: it confidently buries falsehoods within seemingly well-researched answers. Across a dozen topics I’ve explored, I’ve encountered anywhere from a couple (2-3) to over half a dozen hallucinations in each query. When I ask Perplexity whether something is wrong or to ‘check its work’, it usually admits the error and provides corrected information. But that’s of little comfort if you’re faced with a few thousand words created specifically to help you learn about something you haven’t mastered!
And I’m not alone—reviews, including a particularly pointed critique on Everyday AI’s podcast1, call this flaw a near-fatal one.
ChatGPT’s Deep Research: Pricey, But Accurate
I haven’t tested OpenAI’s Deep Research mode myself (it’s locked behind the $200/month Pro plan), but many reviewers agree: it has a notably low hallucination rate and impressive accuracy. If budget isn’t an issue and reliability is paramount, ChatGPT’s Deep Research might be the best option.
*** Update Feb 25! OpenAI added Deep Research to the Plus/Team plans. You get 10 Deep Research queries every 30 days. See these FAQs for more info. This does make ChatGPT my preferred Deep Research tool, though those 10 queries could disappear quickly!
Google Gemini: My Current Pick
For now, Google’s Gemini is shaping up as my go-to Deep Research tool. It’s been around long enough for plenty of reviews, and while hallucinations still happen, they tend to be mild—more of a gentle caution than a deal-breaker. For those of us who don’t need AI for rigorous academic or legal research, Gemini strikes a solid balance between accuracy and affordability. The free plan gives you five Deep Research queries per day, and for $20/month, you get more—without the steep cost of ChatGPT Pro.
Final Verdict: Use With Caution
Deep Research tools are a huge leap forward in AI-powered information gathering. If you need a broad overview or want to pull together insights from multiple sources quickly, they’re fantastic. But here’s the big BUT: when it comes to actually using the information…
Set aside extra time to fact-check. Hallucinations are still part of the package.
That said, I’m keeping my eye on Perplexity. I really like how Perplexity formats information (familiar to those who use Google or Wikipedia), its easy-access source citations, and its speed. But until I have more confidence in the veracity of its Deep Research reporting, Gemini’s going to be my go-to app for answering bigger questions.
In short: Be excited. Be amazed. Use these tools! But above all…
Make Good Choices.