GPT-5.5 hallucinates 3x more than MIT-licensed GLM-5.2(arrowtsx.dev)
573 points by oshrimpton 46 days ago | 291 comments
tl;dr: Open-weight GLM-5.2 (753B params) scores within 4 points of GPT-5.5 on the AA Intelligence Index while hallucinating far less (28% vs 86%), suggesting that scaling parameters and training data has plateaued and often worsens uncertainty calibration. The author argues models should be evaluated on a trilemma of raw capability, hallucination rate, and compute efficiency rather than size alone, citing a coding test where DeepSeek V4 Pro burned 10x more reasoning tokens to produce a confidently wrong answer that GLM-5.2 solved in 12 seconds.
HN Discussion:
  • Skepticism that bigger models cause more hallucination, contradicting recent trends
  • ~Hallucination rate metrics are conditional and shouldn't be attributed solely to model size
  • RLVR could easily train models to say 'I don't know' on uncertain answers
  • Raw accuracy matters more than abstention; verifiable answers preferred over 'I don't know'
  • Suspicion that the article is self-promotional, cherry-picking rate over overall accuracy