SEMPITE AI Visibility Index, 2026-09 edition: public data
https://sempite.com/research/ai-visibility-index/
License: CC BY 4.0. Cite as: SEMPITE AI Visibility Index, 2026-09, sempite.com/research/ai-visibility-index/

WHAT IT MEASURES
For 50 local markets (plumber, dentist, personal injury lawyer, real estate agent, HVAC contractor
x New York, Los Angeles, Chicago, Houston, Phoenix, Philadelphia, San Antonio, San Diego, Dallas, Miami)
we take the top 3 Google Maps businesses and check whether AI assistants name them when asked for a
recommendation. A business counts as "mentioned" if avi_matcher.py finds its name (or its website) in the answer.

FILES
results.csv    month, category, city, engine, maps_position (1-3), business, domain, rating, reviews,
               mentioned (True/False), answer_truncated (True where the stored answer was cut short)
summary.json   every published rate, per month and engine, with 95% Wilson intervals
answers.json   the Google top 3 and every AI answer in full, per market, with the prompts used
avi_matcher.py.txt  the matching rule, saved as .txt for the web: rename to avi_matcher.py.
              It (Python 3, no dependencies). Re-run it over answers.json to reproduce results.csv.

ENGINES
chatgpt       gpt-4o-mini, web search off (answers from the model's own knowledge)
chatgpt_web   gpt-4o-mini, web search on (September 2026 onward)
google_ai     Google AI Mode
Engines with no answer for a market are excluded from that market, never counted as a miss.

KNOWN LIMITS
August 2026 AI Mode answers were stored truncated and are excluded from published rates.
July 2026 raw data no longer exists. July and August 2026 figures published before 18 September 2026
used an earlier matching rule that overstated visibility; see the correction on the page.