CT-UT Exam Dumps - ISTQB Certified Tester Usability Tester

Formative usability evaluation is conducted during the development process to identify usability problems and improve the product iteratively. It is diagnostic and improvement-focused. Summative evaluation, on the other hand, is done after development to assess the final product’s usability, measuring how well it meets defined usability goals. Therefore, the correct distinction is that formative evaluation focuses on improvement, and summative evaluation assesses the outcome. This distinction aligns with widely accepted models such as those defined by ISO 9241-210 and usability.gov.

SUS (System Usability Scale), SUMI (Software Usability Measurement Inventory), and WAMMI (Website Analysis and Measurement Inventory) are all validated, standardized usability questionnaires that support benchmarking. They allow comparison against known usability scores from a wide variety of systems. These instruments provide numeric scores that can be interpreted using benchmark datasets or industry standards. Therefore, all three—i, ii, and iii—are true, making D the correct answer.

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.

An informal usability review can be conducted by anyone, including stakeholders or developers, and does not require formal usability training or qualifications. It is typically subjective and based on general impressions. In contrast, an expert usability review (also called heuristic evaluation) is conducted by a trained usability expert who applies recognized usability principles. This is what differentiates the two approaches most clearly. Options A and C are misleading; expert reviews can be informal in format, and informal reviews aren't necessarily based solely on opinion. Option D is incorrect since both informal and expert reviews can be conducted individually or in groups.

A usability test session is a controlled period during which a test participant performs tasks using the system under test while being observed by a moderator and sometimes additional stakeholders or observers. The goal is to understand how users interact with the interface and identify usability problems. Option A describes an individual task, not the whole session. Option C refers to a test plan or test script, and Option D describes a test technique rather than a usability session. Thus, option B provides the most accurate and comprehensive definition.