{
 "question": "Among the Google Maps top 20 for a local search, which businesses does ChatGPT list, and do the same signals hold across repeat runs, rewordings and a second day?",
 "population": "Google Maps top 20 for the 120 searches of study 9 (US, UK, Canada, Australia), pulled on 26 and 27 September 2026, paired with 898 ChatGPT answers that showed a business list (960 collected): the original question once on 26 September; three repeats and four rewordings on 27 September. 16,294 business-answer pairs.",
 "inclusion": "Each Maps business labeled listed or not listed in each answer, by study 9's branch-aware entity resolution (same branch only).",
 "exclusion": "62 answers where ChatGPT showed no business list.",
 "calculations": [
  "Review, photo and rating comparisons are within each search (above or below that search's median).",
  "Within-band difference: listing-rate difference with vs without a signal inside Maps rank bands 1-3, 4-10, 11-20, weighted by band size, per answer set; 95% intervals by bootstrap over searches (500 resamples).",
  "Pooled model: logistic regression (GEE, independence working correlation, clustered by search) with rank band, five signals, country, service, reworded question and day; average marginal effects with 95% intervals from 200 bootstrap resamples of searches (seed 20260928).",
  "Stability: Jaccard overlap of listed Maps businesses between answers to the same search; listing frequency across three repeats; effective number of businesses (1 / sum of squared listing shares) across the seven 27 September answers."
 ],
 "limitations": [
  "Associations, not causes; retrieval is not observed.",
  "Two collection days.",
  "Maps collected at country level for a city search.",
  "ChatGPT listings outside the Maps top 20 (45.1% on 27 September) are not analyzed.",
  "Matching validated by model coders, not people."
 ],
 "update": "quarterly",
 "@context": "https://schema.org",
 "@type": "Dataset",
 "name": "Which Google Maps businesses does ChatGPT recommend?",
 "version": "1.1",
 "dateCreated": "2026-09-26",
 "creator": {
  "@type": "Organization",
  "name": "Underneath",
  "url": "https://underneath.agency"
 },
 "url": "https://underneath.agency/research/chatgpt-local-picks-google-profile-study",
 "temporalCoverage": "2026-09-26/2026-09-27",
 "isAccessibleForFree": true,
 "license": "https://creativecommons.org/licenses/by/4.0/",
 "code": "cite/pipeline/s14_v11.py, s14_v11_package.py (version 1.1); s14_analyze.py (version 1.0)",
 "variableMeasured": [
  "listed",
  "maps_rank",
  "reviews_above_search_median",
  "rating_4_8_plus",
  "rating_above_search_median",
  "photos_above_search_median",
  "stuffed_name",
  "variant",
  "run",
  "wave"
 ],
 "dateModified": "2026-09-28"
}