CT-UT Exam Dumps - ISTQB Certified Tester Usability Tester

Usability is defined in ISO 9241-11 as the extent to which a system can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use. Without knowing the context—such as product complexity, user familiarity, device type, or purchasing habits—it is impossible to judge whether five minutes is good or bad. For complex items, five minutes may be reasonable, while for one-click purchases, it may be excessive. Thus, usability cannot be assessed solely based on one metric like time—it must be evaluated within its full usage context.

Human-centered design, as defined by ISO 9241-210, emphasizes early user involvement, iterative design, and continuous usability evaluation. Option D aligns with this model as it begins with understanding user needs (interview users), proceeds through iterative prototyping (which allows for continuous improvement), and involves user evaluation. This ensures that the final product is shaped by real user input and feedback. Options A and B lack iteration and continuous evaluation, while option C, although partially aligned, lacks explicit user involvement in the evaluation process, focusing only on expert reviews.

When actual users cannot be included, a usability review (often an expert or heuristic evaluation) is the most practical method. Trained evaluators examine the interface against usability principles and standards to identify potential issues. Surveys require user input, and usability testing cannot proceed without users. Accessibility evaluation targets inclusivity for users with impairments, which is related but not a substitute for overall usability evaluation. Therefore, option A is the only valid method under these constraints.

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.