{
 "date": "2026-11-13",
 "prompts": 45,
 "qa": 30,
 "writing": 15,
 "method": "Same 45 prompts per model via OpenAI Chat Completions, no system prompt, reasoning_effort=low where supported, max_completion_tokens=2500. Em dash = U+2014. Negation family regexes match the gounslop checker. Human/2022 baselines from HC3 (gounslop study, 2026-11-12).",
 "summary": "ChatGPT's default model used 0.75 em dashes per 1,000 words, but the GPT-5.5 to GPT-6.1 API models used 3.8 to 9.2 (human answers to the same questions: 0.21)",
 "old_models": "GPT-4o-mini 1.37, GPT-5.4-mini 1.81",
 "models": [
  {
   "model": "chat-latest",
   "released": "ChatGPT default",
   "answers": 45,
   "words": 22607,
   "em_dashes": 17,
   "em_per_1k": 0.75,
   "em_per_1k_qa": 0.66,
   "em_per_1k_writing": 1.34,
   "pct_with_em": 16,
   "neg": 11,
   "neg_per_1k": 0.49,
   "pct_with_neg": 22,
   "rather": 17,
   "rather_per_1k": 0.75,
   "note": "the model ChatGPT serves by default (API alias chat-latest)"
  },
  {
   "model": "gpt-4o-mini",
   "released": "2024",
   "answers": 45,
   "words": 9502,
   "em_dashes": 13,
   "em_per_1k": 1.37,
   "em_per_1k_qa": 0.44,
   "em_per_1k_writing": 3.66,
   "pct_with_em": 16,
   "neg": 11,
   "neg_per_1k": 1.16,
   "pct_with_neg": 20,
   "rather": 0,
   "rather_per_1k": 0
  },
  {
   "model": "gpt-5.4-mini",
   "released": "Mar 2026",
   "answers": 45,
   "words": 10518,
   "em_dashes": 19,
   "em_per_1k": 1.81,
   "em_per_1k_qa": 1.31,
   "em_per_1k_writing": 3.77,
   "pct_with_em": 29,
   "neg": 7,
   "neg_per_1k": 0.67,
   "pct_with_neg": 11,
   "rather": 2,
   "rather_per_1k": 0.19
  },
  {
   "model": "gpt-5.5",
   "released": "Apr 2026",
   "answers": 45,
   "words": 10310,
   "em_dashes": 39,
   "em_per_1k": 3.78,
   "em_per_1k_qa": 3.55,
   "em_per_1k_writing": 4.68,
   "pct_with_em": 47,
   "neg": 8,
   "neg_per_1k": 0.78,
   "pct_with_neg": 13,
   "rather": 4,
   "rather_per_1k": 0.39
  },
  {
   "model": "gpt-5.6-sol",
   "released": "Jun 2026",
   "answers": 45,
   "words": 7696,
   "em_dashes": 54,
   "em_per_1k": 7.02,
   "em_per_1k_qa": 7.52,
   "em_per_1k_writing": 5.26,
   "pct_with_em": 67,
   "neg": 1,
   "neg_per_1k": 0.13,
   "pct_with_neg": 2,
   "rather": 8,
   "rather_per_1k": 1.04
  },
  {
   "model": "gpt-5.6-luna",
   "released": "Jun 2026",
   "answers": 45,
   "words": 9288,
   "em_dashes": 50,
   "em_per_1k": 5.38,
   "em_per_1k_qa": 5.57,
   "em_per_1k_writing": 4.68,
   "pct_with_em": 56,
   "neg": 7,
   "neg_per_1k": 0.75,
   "pct_with_neg": 13,
   "rather": 4,
   "rather_per_1k": 0.43
  },
  {
   "model": "gpt-6-astra",
   "released": "Sep 2026",
   "answers": 45,
   "words": 9039,
   "em_dashes": 63,
   "em_per_1k": 6.97,
   "em_per_1k_qa": 7.64,
   "em_per_1k_writing": 4.35,
   "pct_with_em": 73,
   "neg": 4,
   "neg_per_1k": 0.44,
   "pct_with_neg": 7,
   "rather": 8,
   "rather_per_1k": 0.89
  },
  {
   "model": "gpt-6-sol",
   "released": "Sep 2026",
   "answers": 45,
   "words": 4909,
   "em_dashes": 29,
   "em_per_1k": 5.91,
   "em_per_1k_qa": 7.63,
   "em_per_1k_writing": 2,
   "pct_with_em": 44,
   "neg": 4,
   "neg_per_1k": 0.81,
   "pct_with_neg": 9,
   "rather": 5,
   "rather_per_1k": 1.02
  },
  {
   "model": "gpt-6-luna",
   "released": "Sep 2026",
   "answers": 45,
   "words": 5674,
   "em_dashes": 52,
   "em_per_1k": 9.16,
   "em_per_1k_qa": 9.36,
   "em_per_1k_writing": 8.67,
   "pct_with_em": 71,
   "neg": 4,
   "neg_per_1k": 0.7,
   "pct_with_neg": 9,
   "rather": 0,
   "rather_per_1k": 0
  },
  {
   "model": "gpt-6.1-sol",
   "released": "Sep 2026",
   "answers": 45,
   "words": 8519,
   "em_dashes": 68,
   "em_per_1k": 7.98,
   "em_per_1k_qa": 8.5,
   "em_per_1k_writing": 6.07,
   "pct_with_em": 73,
   "neg": 3,
   "neg_per_1k": 0.35,
   "pct_with_neg": 4,
   "rather": 4,
   "rather_per_1k": 0.47
  },
  {
   "model": "gpt-6.1-terra",
   "released": "Oct 2026",
   "answers": 45,
   "words": 5344,
   "em_dashes": 23,
   "em_per_1k": 4.3,
   "em_per_1k_qa": 4.22,
   "em_per_1k_writing": 4.52,
   "pct_with_em": 40,
   "neg": 2,
   "neg_per_1k": 0.37,
   "pct_with_neg": 4,
   "rather": 3,
   "rather_per_1k": 0.56
  }
 ]
}