this post was submitted on 11 Mar 2026
49 points (94.5% liked)

Technology

82518 readers
4556 users here now

This is a most excellent place for technology news and articles.

Our Rules

  1. Follow the lemmy.world rules.
  2. Only tech related news or articles.
  3. Be excellent to each other!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, this includes using AI responses and summaries. To ask if your bot can be added please contact a mod.
  9. Check for duplicates before posting, duplicates may be removed
  10. Accounts 7 days and younger will have their posts automatically removed.

Approved Bots

founded 2 years ago
MODERATORS
L3s@lemmy.world
enu@lemmy.world
technopagan@lemmy.world
L4s@lemmy.world
L3s@hackingne.ws
49
How Much Do LLMs Hallucinate in Document Q&A Scenarios? A 172-Billion-Token Study Across Temperatures, Context Lengths, and Hardware Platforms [TLDR: 25%] (arxiv.org)
submitted 4 hours ago* (last edited 4 hours ago) by RandAlThor@lemmy.ca to c/technology@lemmy.world
22 comments fedilink hide all child comments
 

Evaluating 35 open-weight models across three context lengths (32K, 128K, 200K), four temperatures, and three hardware platforms—consuming 172 billion tokens across more than 4,000 runs—we find that the answer is “substantially, and unavoidably.” Even under optimal conditions—best model, best temperature, temperature chosen specifically to minimize fabrication—the floor is non-zero and rises steeply with context length. At 32K, the best model (GLM 4.5) fabricates 1.19% of answers, top-tier models fabricate 5–7%, and the median model fabricates roughly 25%.

you are viewing a single comment's thread
view the rest of the comments
[–] hersh@literature.cafe 3 points 1 hour ago* (last edited 1 hour ago) (1 children)

If I understand you correctly: 63.4% odds of having at least one hallucination.

The simple way to calculate the odds of getting at least one error is to calculate the odds of having ZERO, and then inverting that.

If the odds of a single instance being an error is 1%, that means you have a 99% chance of having no errors. If you repeat that 100 times, then it's 99% of 99% of 99%...etc. In other words, 0.99^100 = 0.366. That's the odds of getting zero errors 100 times in a row. The inverse of that is 0.634, or 63.4%.

This is the same way to calculate the odds of N coin flips all coming up heads. It's going to be 0.5^N. So the odds of getting 10 heads in a row is 0.5^10 = ~0.0977%, or 1:1024.

Edit: This is assuming independence of all 100 prompts, which is not generally true in a single chat window, where each prompt follows the last and retains both the previous prompts and answers in its context. As the paper explains, error rate tends to increase with context length. You should generally start a new chat rather than continue in an existing one if the previous context is not highly relevant.

[–] CubitOom@infosec.pub 2 points 1 hour ago

Thanks, I also wonder how context collapse affects the fabrication rate.