Citation share by source type
Share of all citations by the type of site cited.
| Source type | Four AI engines (of 2,321 citations) | Google AI Overviews (of 286 citations) |
|---|
| Other / unclassified | 945 (40.7%) | 134 (46.9%) |
| Company / brand sites | 452 (19.5%) | 31 (10.8%) |
| Official / government | 191 (8.2%) | 6 (2.1%) |
| Review / comparison publishers | 178 (7.7%) | 7 (2.4%) |
| General news / business press | 162 (7%) | 5 (1.7%) |
| Health publishers | 105 (4.5%) | 23 (8%) |
| Reference | 86 (3.7%) | 1 (0.3%) |
| Community / social | 61 (2.6%) | 62 (21.7%) |
| Institutions / trade bodies | 52 (2.2%) | 6 (2.1%) |
| Directories / rankings | 39 (1.7%) | 5 (1.7%) |
| Trade / specialist press | 27 (1.2%) | 1 (0.3%) |
| Research / data providers | 23 (1%) | 5 (1.7%) |
How can a brand get its facts onto the sites AI engines cite?
These steps follow from the measured results above. They describe what the engines cited in this study and are not a guarantee of results.
| Step | What this study measured |
|---|
| Put your facts on your own domain. | National Institutes of Health's own domains were cited in 9.1% of grounded answers, Wikipedia's in 8.7% and Forbes' in 8.7%. National Institutes of Health was named in only 1.7% of answers, yet its own domains were cited in 9.1%. |
| Keep your facts accurate on the sites engines cite. | The most-cited sites other than the tracked names' own were nerdwallet.com (in 10.9% of grounded answers), healthline.com (8.4%), aad.org (5.8%), thepointsguy.com (5.5%) and mayoclinic.org (5.1%). Official and government supplied 8.2% of citations and review and comparison publishers 7.7%. |
| Check each engine separately. | ChatGPT named Wikipedia in 12.5% of answers against 0.0% on Gemini. ChatGPT named Microsoft in 6.9% of answers against 1.4% on Gemini. |
| Do not ignore video and community sites. | Community and social sites supplied 11.0% of Google AI Overview citations against 2.6% in the four chat engines. youtube.com was cited in 32.8% of overviews, reddit.com in 15.6% and facebook.com in 6.3%. |
| Re-run the same questions every month. | Compare counts and intervals, not ranks. The 24 questions are in the appendix. |
5W, a PR, creative and AI Visibility agency, does this work for clients. See the AI visibility agency page for how it works.
Frequently asked questions
Which tracked platforms are cited most often?
National Institutes of Health was cited most among 48 tracked platforms, but five others are within its margin. National Institutes of Health: 25/275 (9.1%; 95% interval 6.2–13.1%). Forbes: 24/275 (8.7%; 95% interval 5.9–12.7%). Their 95% intervals overlap; neither can be called the sole leader. The ranking covers tracked platforms only. Untracked cited domains include nerdwallet.com (30 answers), healthline.com (23 answers), aad.org (16 answers), thepointsguy.com (15 answers), mayoclinic.org (14 answers), nolo.com (13 answers), americanbar.org (11 answers), cerave.com (11 answers), morningstar.com (11 answers), wrike.com (11 answers). Some were cited as often as or more than the tracked leaders.
Which source platform is named first most often?
OpenAI was the first source platform named in 66 of 288 answers, with an average first position of 1.1.
How often do Google AI Overviews appear for these questions?
An overview appeared on 64 of 70 searches (91.4%, CI 82.5–96%). Within those 64 overviews, Google was named most often, in 49 (76.6%).
Which sources do the engines cite?
Across 2,321 four-engine citations, nerdwallet.com was cited most (37 citations, in 30 of 275 grounded answers), followed by pmc.ncbi.nlm.nih.gov (30 citations).
Do ChatGPT, Claude, Gemini and Perplexity cite the same sources?
Only partly. YouTube was cited in 31.9% of Gemini's grounded answers and 0.0% of Claude's, and Wikipedia was cited in 12.5% of ChatGPT's against 1.4% of Gemini's. Check each engine separately.
Is the ranking a complete list of the sources AI engines cite?
No. It covers 48 tracked platforms only. Untracked domains such as nerdwallet.com (30 answers) and healthline.com (23 answers) were also cited often, and some were cited as often as or more than the tracked leaders.
How can a brand get its facts onto the sites AI engines cite?
Put facts on your own domain, keep them accurate on the sites the engines cite most, check each engine separately, include video and community sites, and re-run the same questions every month. 5W's AI visibility agency page describes how 5W does this work for clients.
How this study was measured
24 questions × 3 runs each × 4 AI engines = 288 answers + 70 Google searches · 64 AI Overviews
24 questions asked three times on each of ChatGPT, Claude, Gemini and Perplexity, measured October 30, 2026. United States, English; Google retrieval uses desktop results. Models: gpt-5-mini, claude-sonnet-5-5, gemini-3.6-flash only, sonar-pro. Google AI Overviews come from DataForSEO, not inferred chat answers. Appearance counts returned text, including ungrounded answers; citation rates use grounded answers. Longer overlapping names suppress shorter ones; First mention is the earliest eligible name order. Own-domain rates include declared domains and subdomains; shared parent scopes may count for multiple names and cannot be summed as unique citations.
| Engine | Model IDs called | Asked | Returned | Grounded |
|---|
| ChatGPT | gpt-5-mini | 72 | 72 | 72 |
| Claude | claude-sonnet-5-5 | 72 | 72 | 59 |
| Gemini | gemini-3.6-flash | 72 | 72 | 72 |
| Perplexity | sonar-pro | 72 | 72 | 72 |
| Google AI Overviews | DataForSEO Google SERP (live, advanced) | 70 | 64 shown | 64 |
Own-domain citations count a domain plus all its subdomains, with the same rule in every table.
Definitions
- Citation penetration: grounded answers citing tracked platform domains ÷ grounded answers, with Wilson 95% intervals. Text mentions remain separate in the evidence.
- First mention: average order in which the tracked name first appears (1 = first).
- Own-domain citation: grounded answers citing the tracked name's domains ÷ grounded answers.
- Citation share: citations to the tracked name's domains ÷ all citations.
Limits
- Only 48 tracked source platforms are ranked; results are not an exhaustive market ranking.
- 358 of 360 planned results were returned. 2 AI Overview lookups were excluded after at most three total attempts.
- 70 successful Google searches: 64 overviews shown; 6 without an overview. Failures are excluded, not scored as zero.
- 13 chat answers had no search sources and are left out of the citation figures.
- No Core question names a tracked name.
- Unverified own domains are not available, never zero or guessed. Source types use Company / brand sites only for verified official organisations; other unresolved sites are Other / unclassified.
- Wilson 95% intervals are descriptive; overlapping leading intervals do not establish a sole leader. Measurements do not endorse medical, legal, financial or product claims.
- The 48 tracked platforms come from the original report's source lists. Each platform counts its domain and subdomains (for example nih.gov and pmc.ncbi.nlm.nih.gov); corporate sites such as redditinc.com are not added to the platform. Each of the eight sectors has three questions.
- The ranking covers tracked platforms only. Untracked cited domains include nerdwallet.com (30 answers), healthline.com (23 answers), aad.org (16 answers), thepointsguy.com (15 answers), mayoclinic.org (14 answers), nolo.com (13 answers), americanbar.org (11 answers), cerave.com (11 answers), morningstar.com (11 answers), wrike.com (11 answers). Some were cited as often as or more than the tracked leaders.
- Google Shopping links and Google redirect URLs are not counted as cited sources in the AI Overview figures; original URLs remain in the evidence.
- For which publishers AI engines name and cite across topics, see the 5W State of AI Citations report.
- Answers came from each engine's API (model IDs above); the consumer apps can answer differently.
Appendix: The 24 questions
Questions marked "Core question" are the original study questions, asked word for word. The others are added neutral questions.
| # | Question | Group | Source |
|---|
| 01 | What is the best project management software for a 50-person company? | Citation Source Audit | Core question |
| 02 | Which CRM is best for a startup? | Citation Source Audit | Core question |
| 03 | What is a good skincare routine for oily skin? | Citation Source Audit | Core question |
| 04 | Which credit card is best for travel rewards? | Citation Source Audit | Core question |
| 05 | What should I look for in a robo-advisor? | Citation Source Audit | Core question |
| 06 | What are the symptoms of vitamin D deficiency? | Citation Source Audit | Core question |
| 07 | What are the best family hotels in Lisbon? | Citation Source Audit | Core question |
| 08 | Is CBD legal in every US state? | Citation Source Audit | Core question |
| 09 | How do I choose a personal injury lawyer? | Citation Source Audit | Core question |
| 10 | What are the healthiest packaged snacks? | Citation Source Audit | Core question |
| 11 | Which running shoes are best for flat feet? | Citation Source Audit | Core question |
| 12 | How do I find a good family dentist? | Citation Source Audit | Core question |
| 13 | Which project management platforms publish pricing for US business customers? | Citation Source Audit | Added question |
| 14 | Which skincare ingredients have evidence for reducing acne? | Citation Source Audit | Added question |
| 15 | How do mineral and chemical sunscreens differ? | Citation Source Audit | Added question |
| 16 | How do robo-advisor fees compare with traditional financial advisor fees? | Citation Source Audit | Added question |
| 17 | Which packaged snack brands publish sodium and added sugar content? | Citation Source Audit | Added question |
| 18 | What are the common symptoms of seasonal allergies? | Citation Source Audit | Added question |
| 19 | Which US national parks offer family accommodation nearby? | Citation Source Audit | Added question |
| 20 | What are the main differences between hotel loyalty programs? | Citation Source Audit | Added question |
| 21 | What is the difference between hemp-derived CBD and marijuana-derived CBD? | Citation Source Audit | Added question |
| 22 | What information appears on a US cannabis product label? | Citation Source Audit | Added question |
| 23 | What is the difference between a personal injury claim and a lawsuit? | Citation Source Audit | Added question |
| 24 | How do contingency fees work in US legal cases? | Citation Source Audit | Added question |
About 5W
5W is an independent PR, creative and AI Visibility agency founded in 2003, and we get you in the chatbox. All of our work is done in house, including media relations, site building and content. Learn more about our AI visibility agency and GEO practice, or write to info@5wpr.com.
