In short
- Prompt testing = systematically testing how AI talks about your brand
- Build a set of 20-50 relevant prompts
- Test monthly in ChatGPT, Perplexity, Gemini
- Measure mention rate, citation rate, correctness
- Document everything for trend analysis
You can't improve what you don't measure. That applies to AI visibility too. Prompt testing is the foundation of your measurement strategy.
What is prompt testing?
Prompt testing is systematically testing how AI tools respond to questions relevant to your brand. You ask the same questions regularly and document the answers.
The difference from ad-hoc testing: consistency. Only with the same prompts over time can you see trends.
Building a test set
Step 1: Categorize your prompts
Brand queries (5-10 prompts)
- "What does [your company] do?"
- "Is [your company] reliable?"
- "What are reviews about [your company]?"
Service queries (5-10 prompts)
- "Best [your service] in Belgium"
- "What does [your service] cost?"
- "Who offers [your service]?"
Comparisons (5-10 prompts)
- "[You] vs [competitor]"
- "Top 10 [your category]"
- "Alternatives to [competitor]"
Definitions (5-10 prompts)
- "What is [core concept]?"
- "How does [process] work?"
Problem/solution (5-10 prompts)
- "How do I solve [problem]?"
- "Help with [challenge]"
Step 2: Refine your prompts
Bad prompt: "marketing" Good prompt: "Best B2B marketing agency in Belgium for SaaS companies"
Bad prompt: "CMO" Good prompt: "What does a fractional CMO cost for a scale-up?"
Step 3: Prioritize
Start with 20-30 prompts. Expand later. Quality over quantity.
The test protocol
Which tools to test?
Minimum:
- ChatGPT (with web search on)
- Perplexity
Extended:
- ChatGPT
- Perplexity
- Gemini
- Claude
How to document?
Create a spreadsheet with columns:
- Prompt ID
- Prompt text
- Tool
- Date
- Mention (Y/N)
- Citation with link (Y/N)
- Correctness (1-5)
- Screenshot link
- Notes
How often to test?
- Minimum: monthly
- Optimal: bi-weekly
- After major content updates: immediately
What do you measure?
Mention rate
Formula: (Prompts with mention / Total prompts) × 100
Example: 8 of 30 prompts = 26.7% mention rate
Citation rate
Formula: (Mentions with link / Total mentions) × 100
Example: 5 of 8 mentions have link = 62.5% citation rate
Correctness score
Rate each mention on correctness: 1 = Completely incorrect 3 = Partially correct 5 = Completely correct
Average over all mentions = correctness score.
Trend over time
Plot your metrics monthly. Rising line = progress.
Avoiding pitfalls
Inconsistent prompts
Don't change your prompts in between. Then you can't compare.
Too little documentation
Screenshot everything. You'll need it later for analysis.
Only looking for positives
Also document where you DON'T appear. Those are your opportunities.
Too quick conclusions
AI models update irregularly. Give it at least 3 months.
From testing to action
After each test round:
- Analyze gaps: Which prompts don't yield a mention?
- Identify patterns: What do successful prompts have in common?
- Prioritize fixes: Focus on high-impact prompts
- Implement: Update/create content
- Retest: Test again after 4-6 weeks
Example reporting
Monthly Report January 2026
Summary
- Mention rate: 26.7% (+4% vs December)
- Citation rate: 62.5% (+12% vs December)
- Correctness: 4.2/5 (stable)
Wins
- First citation in Perplexity for "fractional CMO Belgium"
- Correct mention in Gemini for brand query
Gaps
- No mentions for comparison prompts
- Competitor X dominates category queries
Actions next month
- Create comparison page X vs Y
- Expand FAQ with pricing info
- Add case study
FAQ
Can I automate prompt testing?
Partially. Tools are emerging, but manual testing gives more insight.
How much time does it take?
2-3 hours per month for 30 prompts in 2 tools.
What if my results don't improve?
Analyze why. Often: content not citable enough or technical blockers.
Need help? MatthCon sets up complete prompt testing programs. Schedule a call.