How the AI Visibility Benchmark was measured
The full methodology behind the Dutch AI Visibility Benchmark: all 45 prompts, exact model versions, every definition, Wilson 95% confidence intervals, and the complete dataset of 1,125 answers as an open CC BY 4.0 download.
Table of Contents
Why this appendix
The AI Visibility Benchmark is research by a company that also sells services in the field it studies. That is called vendor research, and it is entirely common: Ahrefs, Semrush and HubSpot publish the same way. But it also means you should not have to take my numbers on faith. You should be able to check them.
That is what this page is for. It contains everything needed to verify or redo the measurement: the exact questions, the exact model versions, the definitions behind every metric, the uncertainty margins on every claim, and the complete dataset of all 1,125 answers as a free download under a CC BY 4.0 license. Nothing is summarized, nothing is left out, nothing is cleaned up.
The design in numbers
| Element | Value |
|---|---|
| Professions | 3 (architects, therapists, photographers) |
| Questions per profession | 15 (10 recommendation questions, 5 recognition questions) |
| AI assistants | 5 (ChatGPT, Google Gemini, Perplexity, Claude, Grok) |
| Repetitions per question | 5, each with a clean context |
| Answers per profession | 375 |
| Answers total | 1,125 |
| Measurement window | June 10, 2026, 05:20 UTC through June 12, 2026, 09:21 UTC |
The recommendation questions spread across three region layers per profession: five national, three metropolitan, two regional. Every API call got a clean context: no memory, no system instructions, no session carry-over. A fixed two second delay separated calls. Grok was added as the fifth platform on June 12, after a trial run on the therapist set came back error-free; all three professions were then measured in full on Grok.
All 45 prompts
The prompt set was fixed up front and not changed during the measurement. That is verifiable in the dataset itself: every raw answer contains the exact prompt text that was sent, timestamped. The questions are phrased in natural buyer language, the way a client actually asks them, not in trade jargon. All prompts are in Dutch, because the buyers are.
Type A is a category question, type B a problem question where the asker does not yet know which specialist they need, type C a name verification. For type C, {expert_name} was filled in per run with one of the five sampled experts per profession.
Architects
| ID | Type | Region | Prompt (Dutch original) |
|---|---|---|---|
| arch-a-01 | A | national | Wie is een goede architect voor circulair bouwen in Nederland? |
| arch-a-02 | A | national | Welke architecten in Nederland zijn gespecialiseerd in herbestemming van industrieel erfgoed? |
| arch-a-03 | A | national | Ik wil een huis in houtbouw laten ontwerpen. Welke architect raad je aan? |
| arch-a-04 | A | metro | Wie is een goede architect in Amsterdam voor een duurzame verbouwing van een jaren 30 woning? |
| arch-a-05 | A | metro | Welke architectenbureaus in Rotterdam zijn goed in het transformeren van kantoorpanden naar woningen? |
| arch-a-06 | A | regional | Ik zoek een architect in de regio Breda voor een nieuwbouwwoning in hout. Wie kun je aanraden? |
| arch-b-01 | B | national | Ons pand uit de jaren vijftig moet verduurzaamd worden. Wat voor expert heb ik daarvoor nodig en wie doet dit goed? |
| arch-b-02 | B | regional | We willen onze oude boerderij in Brabant herbestemmen tot een plek om te wonen en te werken. Welke specialist moet ik inschakelen en wie is daar goed in? |
| arch-b-03 | B | national | Onze kerk staat leeg en de gemeente wil er een nieuwe functie aan geven. Wie kan ons hierbij helpen? |
| arch-b-04 | B | metro | Ik wil een aanbouw aan mijn huis met zo min mogelijk milieubelasting. Wat voor expert zoek ik en wie zou je aanbevelen in de buurt van Rotterdam? |
| arch-c-01 to 05 | C | national | Wie is {expert_name}? |
Therapists
| ID | Type | Region | Prompt (Dutch original) |
|---|---|---|---|
| ther-a-01 | A | national | Wie is een goede traumatherapeut met EMDR in Nederland? |
| ther-a-02 | A | national | Ik zoek een relatietherapeut voor mij en mijn partner. Wie raad je aan in Nederland? |
| ther-a-03 | A | national | Welke psycholoog in Nederland is gespecialiseerd in burn-out en overspannenheid? |
| ther-a-04 | A | metro | Wie is een goede psycholoog in Amsterdam voor de behandeling van angst- en paniekklachten? |
| ther-a-05 | A | metro | Welke therapeut in Rotterdam is goed in het behandelen van trauma en PTSS? |
| ther-a-06 | A | regional | Ik zoek in de regio Breda een relatietherapeut. Wie kun je aanraden? |
| ther-b-01 | B | national | Sinds een ingrijpende gebeurtenis slaap ik slecht en schrik ik overal van. Wat voor hulp heb ik nodig en wie is daar goed in? |
| ther-b-02 | B | regional | Het loopt al tijden stroef tussen mij en mijn partner en we komen er samen niet uit. Welke specialist moet ik inschakelen en wie is daar goed in in de regio Eindhoven? |
| ther-b-03 | B | national | Ik ben volledig opgebrand door mijn werk en mijn huisarts adviseert begeleiding. Wat voor expert heb ik daarvoor nodig en wie doet dit goed? |
| ther-b-04 | B | metro | Ik krijg steeds vaker paniekaanvallen en ga situaties uit de weg. Wat voor hulpverlener moet ik zoeken en wie zou je aanbevelen in de buurt van Rotterdam? |
| ther-c-01 to 05 | C | national | Wie is {expert_name}? |
Photographers
| ID | Type | Region | Prompt (Dutch original) |
|---|---|---|---|
| pho-a-01 | A | national | Wie is een goede trouwfotograaf in Nederland? |
| pho-a-02 | A | national | Welke fotograaf in Nederland is gespecialiseerd in familie- en portretfotografie? |
| pho-a-03 | A | national | Ik zoek een fotograaf voor zakelijke portretten en personal branding. Wie raad je aan in Nederland? |
| pho-a-04 | A | metro | Wie is een goede bruiloftsfotograaf in Amsterdam? |
| pho-a-05 | A | metro | Welke fotograaf in Rotterdam is goed in zakelijke bedrijfs- en brandingfotografie? |
| pho-a-06 | A | regional | Wie is een goede trouwfotograaf in de regio Breda? |
| pho-b-01 | B | national | We gaan volgend jaar trouwen en willen de dag mooi laten vastleggen. Wat voor fotograaf zoeken we en wie is daar goed in? |
| pho-b-02 | B | regional | We willen graag professionele foto's van ons gezin laten maken nu de kinderen nog klein zijn. Welke specialist kunnen we daarvoor het beste inschakelen en wie is daar goed in in de regio Eindhoven? |
| pho-b-03 | B | national | Ik start een eigen bedrijf en heb professionele foto's nodig van mezelf en mijn werk voor mijn website en LinkedIn. Wat voor fotograaf heb ik daarvoor nodig en wie doet dit goed? |
| pho-b-04 | B | metro | Mijn ouders zijn veertig jaar getrouwd en we geven een groot feest dat we graag willen laten vastleggen. Wat voor fotograaf zoek ik en wie zou je aanbevelen in de buurt van Rotterdam? |
| pho-c-01 to 05 | C | national | Wie is {expert_name}? |
Models and settings
All five assistants were queried through their APIs, with web search or grounding enabled, the way the average user has them in the consumer app. The table shows both the configured model name and the model version each API reported back. The latter is recorded per individual answer in the model_reported field and is the ground truth; models shift under your hands.
| Platform | Configured | Reported by the API | Search |
|---|---|---|---|
| ChatGPT | gpt-5 | gpt-5-2025-08-07 | web search on |
| Google Gemini | gemini-flash-latest | gemini-3.5-flash | search grounding on |
| Perplexity | sonar | sonar | built in |
| Claude | sonnet | claude-sonnet-4-6 | web search on |
| Grok | grok-4.3 | grok-4.3 | web and X live search on |
Two honest footnotes. The Claude measurements ran through the official CLI; for 149 of the 225 Claude answers it reports an internal helper model (claude-haiku-4-5) alongside Sonnet, which did not write the answer but drove CLI tooling. That is visible in the data rather than cleaned away. And the Gemini configuration used the gemini-flash-latest alias, which pointed to gemini-3.5-flash during the measurement window; since July we pin the explicit version name, because an alias can jump mid-window.
The sample
The expert sample per profession was compiled exclusively through neutral sources: professional registers, trade associations and trade media, among them the BNA, the Dutch EMDR Association, the NVRG, the NIP, DuPho, the BIG register and trade titles such as De Architect and Het Houtblad. Emphatically not through AI suggestions, because then you measure what AI already knows, and not from my own network, because then you measure who I already know. Every list was reviewed by hand before any run.
For the recognition questions (type C), five experts were selected per profession, spread across prominence: one nationally prominent, two mid-field, two with a small public profile. For each expert an entity snapshot was recorded: own domain, schema.org present, Wikipedia and Wikidata, LinkedIn activity, trade media mentions, and name ambiguity. Those snapshots ship in full with the dataset, so you can test the relation between entity position and recognition yourself.
Definitions
Every metric in the report rests on an explicit definition. Here they are.
- Named answer. A recommendation answer (type A or B) counts as named when at least one concrete person or organization was extracted from it and it is not a refusal. Generic advice without names does not count.
- Mention. One named person or organization in one answer, after name normalization (lowercased, accents and punctuation stripped). The core metric is frequency across the five repeat runs of the same question: in how many of the five runs does expert X appear?
- Consistency. Jaccard overlap of the set of named entities between identical repeat runs of the same question on the same platform.
- Recognized (type C). The answer demonstrably describes our sampled expert, verified by hand against firm, region and profession. An answer describing a namesake, or a convincing sounding but confabulated person, counts as not recognized. All 375 recognition answers were reviewed manually. The original automated recognition field sits next to the manual verdict in the dataset, so you can see exactly where the two differ and why the manual step was necessary.
The extraction of persons, organizations and source links from the answers was done by a language model (claude-sonnet-4-6). The first fifty extractions per profession were validated by hand before the rest was processed.
Uncertainty: confidence intervals
AI answers vary, and a sample is a sample. Every percentage in the report therefore carries an uncertainty margin, and it belongs in the open. Below are the Wilson 95% confidence intervals for the core numbers. Read them like this: where the interval is wide, the point estimate is an indication, not a precision instrument.
Name ratio per platform (share of recommendation answers with at least one name, n=50 per cell)
| Platform | Architects | Therapists | Photographers |
|---|---|---|---|
| ChatGPT | 80.0% (67.0 to 88.8) | 92.0% (81.2 to 96.9) | 86.0% (73.8 to 93.0) |
| Gemini | 100% (92.9 to 100) | 100% (92.9 to 100) | 100% (92.9 to 100) |
| Perplexity | 98.0% (89.5 to 99.7) | 90.0% (78.6 to 95.7) | 100% (92.9 to 100) |
| Claude | 100% (92.9 to 100) | 94.0% (83.8 to 97.9) | 94.0% (83.8 to 97.9) |
| Grok | 100% (92.9 to 100) | 100% (92.9 to 100) | 100% (92.9 to 100) |
| All five combined (n=250) | 95.6% (92.3 to 97.5) | 95.2% (91.8 to 97.2) | 96.0% (92.8 to 97.8) |
Recognition of the correct person per expert (n=25 per expert)
| Profession | Expert | Recognized | Share | 95% interval |
|---|---|---|---|---|
| Architects | Thomas Rau | 25/25 | 100% | 86.7 to 100 |
| Architects | Daan Bruggink | 25/25 | 100% | 86.7 to 100 |
| Architects | Janneke Bierman | 25/25 | 100% | 86.7 to 100 |
| Architects | Sander van Sambeek | 24/25 | 96.0% | 80.5 to 99.3 |
| Architects | Bart Spee | 10/25 | 40.0% | 23.4 to 59.3 |
| Therapists | Carien Karsten | 25/25 | 100% | 86.7 to 100 |
| Therapists | Gerard Dikschei | 25/25 | 100% | 86.7 to 100 |
| Therapists | Anneke Notermans | 24/25 | 96.0% | 80.5 to 99.3 |
| Therapists | Stefi van de Graaf | 23/25 | 92.0% | 75.0 to 97.8 |
| Therapists | Cora van Dijk | 5/25 | 20.0% | 8.9 to 39.1 |
| Photographers | Marie Cecile Thijs | 25/25 | 100% | 86.7 to 100 |
| Photographers | Carin Deben | 25/25 | 100% | 86.7 to 100 |
| Photographers | Denise Motz | 24/25 | 96.0% | 80.5 to 99.3 |
| Photographers | Anniek Snoeijs | 23/25 | 92.0% | 75.0 to 97.8 |
| Photographers | Astrid Mitchell | 14/25 | 56.0% | 37.1 to 73.3 |
What these intervals mean for the conclusions: at n=25 per expert the margins are wide, so no single per-expert percentage should be taken to the decimal. The claims in the report therefore rest not on individual point estimates but on patterns that occur in all three professions at once. That in every profession precisely the expert with a famous namesake collapses while experts with an unambiguous name are recognized almost flawlessly is well separated even at these interval widths: the intervals of Bart Spee (23.4 to 59.3) and Cora van Dijk (8.9 to 39.1) nowhere overlap those of the flawlessly recognized experts (86.7 to 100).
The per-platform intervals, including the recognition numbers per platform, are in the confidence-intervals.json file in the dataset, computed with exactly the same definitions as the report.
The full dataset
All 1,125 answers are public, unedited and machine readable, under a CC BY 4.0 license. You may reuse, redistribute and build on them, with attribution. Every claim in the report can be checked against these files.
| File | Contents | Size |
|---|---|---|
| answers.jsonl | All 1,125 answers: full response text, prompt, platform, reported model version, timestamp, run index, cited URLs | 4.7 MB |
| answers-full.jsonl.gz | The same 1,125 answers with the complete, untouched API envelope per answer: the primary evidence | 3.7 MB |
| extracted.jsonl | Per answer the extracted persons, organizations and source links, plus the manual recognition verdict | 3.0 MB |
| prompts.json | All 45 prompts with type, region layer and exact wording | 14 kB |
| experts.json | The expert sample per profession: selection sources, prominence tier, entity snapshot | 78 kB |
| confidence-intervals.json | Wilson 95% intervals for all core proportions | 6 kB |
| manifest.json | Record counts, file sizes and SHA-256 checksums for every file | 1 kB |
| README.md | Datasheet: schema per file, definitions, license, citation | 7 kB |
The checksums in manifest.json make every file verifiable: whoever downloads a file can confirm it is the original, byte for byte.
Citation: Identity First Media (2026). NL AI Visibility Benchmark, baseline Q2 2026.
What this study is and is not
This is vendor research: carried out by Identity First Media, which sells services in the field of AI findability. That double role does not disappear by staying quiet about it, but by compensating it with verifiability. Hence this appendix, the open dataset and the fixed honesty paragraph that ships with every publication.
What this study is: a repeatable baseline of the AI visibility of Dutch domain experts, with every raw observation retained and published.
What it is not: independently validated research. It only becomes that when someone else redoes the measurement and finds comparable patterns. The prompt set, the expert sample and the model configuration in the dataset are sufficient for that. Whoever repeats the measurement against the then current model generation should expect different absolute numbers, because models change continuously. The structural patterns are the claim, not the point estimates. If you redo it and find something else, we will gladly publish that next to ours.
The remaining limits of the measurement, including the difference between API and consumer app, are in the main report.
Related
This is the methodology appendix to the Dutch AI Visibility Benchmark. Background on the core concept: what is an entity?