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Glossary · U

Usability Testing.

Usability Testing is a user research method in which real users complete typical tasks with a product or prototype while being observed. This reveals obstacles before they cost conversions.

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Usability Testing — Explained in Detail

Usability Testing is a central method in UX design. Representative users perform concrete tasks on a website, app or prototype — for example 'find the right product and add it to the cart'. During the test, you observe where users hesitate, misclick or give up. The result is concrete, prioritizable improvements.

A well-known research finding from the Nielsen Norman Group: just five testers uncover around 85% of the most serious usability problems. Usability testing therefore needs to be neither expensive nor lengthy to deliver great value. A distinction is made between moderated tests (a person accompanies the test) and unmoderated tests (users complete tasks independently, often recorded via a tool).

The business benefit is directly measurable: removing obstacles in the ordering or enquiry process increases the conversion rate — often by double-digit percentages. That's why usability testing is a fixed part of every UX project at DLM Digital, before a design goes into development.

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Frequently Asked Questions About Usability Testing

For qualitative tests, 5 people per user group are often enough — they uncover around 85% of problems according to the Nielsen Norman Group. More testers bring diminishing returns. For quantitative statements (e.g. success rates in percent), larger samples are needed.

In a moderated test, a moderator accompanies the tester live and can ask follow-up questions. In an unmoderated test, users complete tasks independently, usually recorded via a tool — faster and cheaper, but without follow-up questions. Both methods complement each other.

Ideally early and iteratively: on the prototype (before development), again before launch and regularly during operation. The earlier a problem is discovered, the cheaper it is to fix.

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