You measure the user-friendliness of a touchscreen kiosk using three key metrics from ISO 9241-11: effectiveness (does the user achieve their goal?), efficiency (how much time and how many steps does that take?), and satisfaction (how does the user experience the interaction?). For installers, this means: test with real users before delivery, measure concrete figures, and document findings so that you have a fair comparison during the next iteration.
Why pre-delivery testing pays off
A technically correctly installed kiosk can still fail if the interface is confusing. Public touchscreens are operated by people with widely varying digital skills — from students to seniors. UX errors cost the client revenue, visitors, or reputation. Pre-delivery testing prevents costly adjustments afterward and positions you as an installer who looks beyond the hardware.
De PixioKiosk (21,5″, price list Q2 2026: €1.395) runs on an integrated Android 13/14 computer — no separate media player needed. This makes it easier to run test scenarios directly on the device without configuring additional hardware.
Method 1: Task analysis with real users
The most direct method is a structured task test. You give test participants a concrete assignment — "find the way to room 3" or "sign up for the event" — and observe without intervening. Measure three things:
- Task completion rate: what percentage of participants complete the task without help?
- Time on task: how many seconds does an average session last?
- Error rate: how many wrong turns or dead ends occur?
For exploratory research, five participants are sufficient to uncover the majority of areas for improvement. If you want statistically reliable figures, aim for at least 15 to 20 participants.
Also pay attention to touch accuracy during the task test: Check the response in the corners and edges of the screen, as that is where problems occur first.Good touchscreens follow the finger without delay or stuttering.
Method 2: the System Usability Scale (SUS)
The SUS is a validated 10-item questionnaire on a 5-point scale, developed by John Brooke in 1986. The result is a score from 0 to 100. A SUS score above 68 is considered above average; above 80, you are in the top 10–15% of all tested systems. — that is the point at which users actively recommend a product.
The SUS is technology-independent: you use the same questionnaire for a 21,5″ information kiosk as for a 49″ floor model. This makes it easy to compare different screen sizes or software versions. Never change the questions — the specific wording has been validated for decades, and modifying it makes comparison with benchmark data impossible.
SUS Interpretation Scale (Sauro & Lewis):
| Score | Qualification | Percentile |
|---|---|---|
| <51 | Unacceptable | Under 15% |
| 51–67 | Marginal | 15-49% |
| 68–80 | Good | 50-89% |
| > 80 | Excellent | Top 10–15% |
Always combine the SUS with qualitative data. The score tells you that there is a problem; observations and think-aloud sessions tell you where and why.
Method 3: heuristic evaluation
In a heuristic evaluation, an expert assesses the interface based on established design principles — without test participants. This is faster and cheaper than a user test, but less representative. Use it as the first filter before deploying test participants.
For public touchscreens, the most relevant heuristics are:
- Visibility of system status: Does the kiosk always provide feedback after a tap?
- Error prevention: are destructive actions (cancel, delete) protected?
- Consistency: are the buttons in the same position on every page?
- Flexibility: does the interface also work for people who have never used a touchscreen?
You can find a complete checklist for museum kiosks in the article. Digital signage in museums: interactive exhibitions and visitor information.
Method 4: performance measurement with logging
In addition to user testing, you can let the kiosk collect data itself. Modern kiosk software on Android 13/14 can log session data: which screens are visited most often, where users drop off, and how long an average session lasts. This provides continuous insights after delivery — without having to constantly recruit test participants.
Set at least three KPIs before going live:
- Task completion rate — aim for > 85%.
- Average session duration — depending on usage; for an information kiosk typically 30–90 seconds.
- Bounce rate — the proportion of sessions where the user drops out after one screen.
De PixioKiosk is available in sizes from 21,5″ to 49″ (€1.395–€2.295, price list Q2 2026)Larger screens provide more space for navigation elements, which can reduce the error rate with complex menus — but only if the interface is also optimized for this.
Iterative optimization: from test result to adjustment
Testing only has value if the findings lead to concrete adjustments. Use a fixed cycle:
- Test — perform task test and SUS measurement.
- Analyze — identify the three biggest bottlenecks.
- Customize — change the interface (button size, label text, navigation structure).
- Retest — measure again with the same tasks and compare the SUS score.
A difference of less than 5 SUS points between two versions is not statistically significant. Aim for improvements of at least 5 to 8 points before considering an adjustment successful.
For accessibility requirements — such as minimum touch surfaces and color contrast for the visually impaired — read the step-by-step plan in Making a touchscreen kiosk WCAG-accessible: step-by-step.
From test to delivery
A structured usability test is not a luxury for large projects — it is the quality assurance that sets you apart as an installer. Document your test results (task completion rate, SUS score, error log) and deliver them along with the hardware. Clients appreciate that transparency, and you have a measurable baseline for future updates.
Do you want to know which screen size best suits your application? View the PixioKiosk product page or ask the current price list look up for a comparison of sizes and lease options.
