CT-UT Exam Dumps : ISTQB Certified Tester Usability Tester

The usability test moderator plays a crucial role during the execution phase of a usability test. Their principal task is to facilitate the test sessions by guiding participants through predefined testing tasks, observing behaviors, and ensuring that the test environment is neutral and free from bias. Defining testing tasks, however, is primarily done during the test design phase by the usability test designer or analyst, but the moderator ensures these tasks are clearly communicated and administered to participants during the session. Logging usability problems (option B) is often done by observers or analysts reviewing session recordings or notes, not directly by the moderator during live testing. Creating a survey plan (option C) and writing the usability test plan (option D) are preparatory activities generally done before the test sessions and are not the moderator's main focus. Therefore, the principal role of the moderator centers on conducting the sessions and managing task delivery effectively to obtain authentic user interaction with the system under test.

A usability requirement specifies how usable a product or component must be, often in terms of effectiveness, efficiency, and user satisfaction, as defined in ISO 9241-11. These requirements ensure that the product meets specific human-centered design goals, such as allowing users to complete tasks accurately and quickly. Options A and C describe procedural or test setup elements, not actual usability requirements. Option B refers to personnel qualifications, which are not the same as usability requirements related to system behavior or performance.

The described issue violates the usability heuristic “User control and freedom,” as defined by Jakob Nielsen. This principle emphasizes that users should have the ability to undo and redo actions and navigate freely without being trapped in irreversible sequences. In the scenario, users are forced into the checkout process without a clear way to return or correct mistakes, except through the unreliable and disruptive back button. This design flaw undermines user autonomy and can result in lost progress or frustration.