Usability Tests in Practice

Usability tests are one of the most effective methods for systematically evaluating the usability of digital products. They not only enable the identification of specific usage problems, but also promote an understanding of users’ ways of thinking and patterns of action. In practice, they form an indispensable basis for evidence-based design decisions - especially in iterative development processes.

How Does a Usability Test Work?

The process of a usability test follows a clearly structured pattern - from the definition of objectives to the derivation of specific measures. In the planning phase, the first step is to formulate key questions: “Is the registration process understood?”, “Are there barriers to the ordering process?” or “Is the navigation intuitive?” This results in hypotheses that are to be tested.

Then realistic tasks are developed, such as: “Imagine you want to book a train ticket to Berlin - how do you go about it?” The wording should be as open and neutral as possible so as not to suggest a solution.

An important success factor is the selection of suitable test subjects. As a rule, five to eight participants are sufficient, provided they represent the target group. For example, a food ordering app can be tested specifically with frequent customers from urban areas, while a B2B dashboard places different demands on recruitment.

During the session, the moderator and/or observer observe the behavior - ideally this is also recorded (e.g. via screen recording). The session is often supplemented by methods such as thinking aloud or short interposed questions (“What do you expect behind this button?”).

The test is followed by a structured evaluation: What went smoothly? Where did errors or uncertainties occur? What feedback was given? From this, concrete recommendations for action can be derived - for example, a reformulation of button labels, a simplification of form fields or a restructuring of the navigation.

Moderated or Unmoderated? A comparison of two variants

In practice, two main variants are used:

In the moderated usability test, the session is actively accompanied - usually via video call or in the test lab. This allows a deeper understanding through targeted questions, but is more complex in terms of organization and implementation. A typical case: a UX team tests a prototype for an insurance tool with a moderated session and learns that terms such as “contribution rate” are not self-explanatory - even though all participants have solved the task technically correctly.

On the other hand, there is the unmoderated test, which is often carried out via specialized platforms. Participants complete the tasks independently, while their clicks and statements are recorded. This variant is particularly suitable for larger samples and simple user flows, such as the evaluation of product pages in the e-commerce sector.

Remote tests (via online platforms such as Lookback, Maze or UsabilityHub) are also becoming increasingly important - not only due to the pandemic, but also for reasons of efficiency. Especially in international projects or with decentralized teams, they enable flexible and cost-effective implementation.

Why Usability Tests? Goals and Benefits

The primary purpose of a usability test is to identify ** problems at an early stage** before they cause high costs in the production phase. In this way, not only effectiveness (e.g. through success rates), but also efficiency (e.g. through time measurement) and satisfaction (e.g. through interviews or questionnaires) can be measured. Usability tests also help to validate design hypotheses, e.g. whether a new navigation concept is really easier to understand - or whether it just seems that way.

Another advantage: the results can be presented very clearly to stakeholders. A short video example in which several users make the same navigation error is often more convincing than a pure report.

Typical Mistakes and How to Avoid Them

A common problem is a non-representative sample. If only internal employees or people with an affinity for technology are tested, it is not possible to make well-founded statements about the actual target group. Equally critical are tasks that are too complex or suggestive and test knowledge about the test rather than the product.

The role division in the test team is also often unclear: Moderators should concentrate on leading the discussion, while observers should focus on documentation - ideally structured with record sheets.

Not to forget: pre-tests (piloting) help to identify technical problems, unclear wording or unusable tasks in advance. And finally, statements should not be interpreted in isolation - but always in connection with behavior, context and, if possible, triangulative data sources.

Conclusion: Usability Tests as a Core Instrument of UX Research

Usability tests are not a nice-to-have, but a methodical backbone of user-centered design. They not only provide concrete information for optimizing individual elements, but also promote a better understanding of the user experience as a whole. Properly planned, carried out in a differentiated manner and soundly evaluated, they make a significant contribution to the quality of digital products - evidence-based, practical and highly effective.

Last modified: 17 June 2025