SEO Recap covering October 18, 2026: Study on reproducing ChatGPT citations via API and Google

Built by Stephanie Chung·2 min read·1 story

Daily summary of what matters in SEO, GEO, AEO, and AI search generated with Claude Code (beware of hallucinations)

Generative Engine Optimization (GEO) & Answer Engine Optimization (AEO)

Study finds OpenAI's API and Google only partly match ChatGPT's citations
Source: Search Engine Journal

  • Researchers from the National University of Singapore and Xi'an Jiaotong University posted arXiv figures on Oct. 11, recording ChatGPT's own signed-in session data flow to capture the searches it ran and the pages it chose as sources across 4 model settings (GPT-5.2 Instant to GPT-5.5 Instant), with most data collected March 29-July 29, 2026.
  • Combining Google organic results (via SerpAPI) and OpenAI's Responses API found 26.2% of the pages GPT-5.5 Instant cited but 48.7% of the sites behind those citations, meaning site-level checks match far better than page-level ones.
  • Google results alone covered just 6.4% of GPT-5.5 Instant's cited pages and 22.8% of cited sites, while the API's full source list covered ~22.5% of cited pages.
  • ChatGPT rewrote queries and varied sources heavily: it never used the original question's exact wording in visible GPT-5.3 and GPT-5.5 runs, searched in English for ~67-70% of Chinese-language prompts, and surfaced ~44.5% of distinct pages in only one of 20 runs.
  • To monitor AI visibility, track at both page and site level, run the same prompt multiple times, account for ChatGPT rewriting prompts, and check whether a tracking tool pulls data from the API or the ChatGPT app directly.
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