ISTQB CT-UT key terms

The degree to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use. It is a quality attribute, not a single test.

The accuracy and completeness with which users achieve specified goals. In usability evaluation it is measured by task success, error rate, and quality of output rather than by speed.

The resources expended in relation to the accuracy and completeness of goals achieved, typically measured as time on task, number of steps, or effort per completed task.

The freedom from discomfort and the positive attitudes of users toward product use. Measured through questionnaires, interviews, and observation of frustration or confidence during task performance.

The users, tasks, equipment, and physical and social environment in which a product is used. Usability claims are only meaningful when this context is stated, because results do not transfer automatically.

An empirical method in which representative users attempt realistic tasks with a product while evaluators observe and record behaviour, difficulties, and comments. It produces evidence about actual use rather than opinion.

The broader activity of assessing usability against defined criteria, which may use empirical testing, inspection methods, or user surveys. Testing is one technique within this activity, not a synonym for it.

An inspection method in which a small number of evaluators independently examine an interface against recognised usability principles and then merge their findings. It finds many issues cheaply but does not involve real users.

An inspection technique where evaluators step through a task sequence from a novice user's perspective, asking at each step whether the user will know what to do and receive useful feedback.

Any evaluation method in which trained reviewers examine an interface without observing real users performing tasks. Examples include heuristic evaluation, cognitive walkthrough, and guideline review.

A technique in which participants verbalise their thoughts, expectations, and reactions while performing tasks. It reveals the reasoning behind actions but can slow performance and increase cognitive load.

A usability test session in which a facilitator is present to give instructions, prompt participants, and probe for explanations. It yields rich qualitative data but risks influencing participant behaviour.

A usability test session run without a facilitator, often remotely with automated task instructions and recording. It enables larger samples and natural settings but offers no probing and higher dropout risk.

Testing in which participants and evaluators are in different locations, using screen sharing or self-recorded sessions. It widens access to diverse users but reduces control over the environment and equipment.

The person who runs a usability session: welcoming the participant, reading task instructions neutrally, and probing without leading. Neutral wording is essential to avoid biasing observed behaviour.

A question that suggests the expected answer, such as asking whether a feature was confusing. It contaminates usability findings and must be avoided in task instructions and post-session interviews.

A document defining the purpose, research questions, participant profile, tasks, metrics, session procedure, and reporting approach for a usability test. It makes results traceable and comparable across iterations.

A person recruited to represent the target user group and to perform tasks during a usability test. Recruitment criteria must match the defined context of use, not merely convenience availability.

A trial run of the test procedure with a stand-in participant before real sessions. It validates tasks, timings, recording equipment, and instructions, exposing problems while they can still be fixed cheaply.

The physical space, hardware, software build, network conditions, and assistive technologies arranged for a usability session. It should approximate the real context of use as closely as practical.

Realistic content and records prepared so participants can perform tasks without hitting artificial dead ends. Poor or empty data can create false usability problems unrelated to the product design.

A document explaining purpose, recording, data handling, and the right to withdraw, signed before a session. It is an ethical prerequisite, not a formality, and must be understandable to participants.

The process of removing or replacing identifying details from recordings, transcripts, and reports so participants cannot be recognised. It supports ethical handling and data protection obligations.

A person's perceptions and responses resulting from actual or anticipated use of a product, covering emotions, beliefs, preferences, and behaviour. It extends beyond task performance to subjective quality.

The sequence of steps and touchpoints a user passes through to accomplish a goal over time. Mapping it exposes gaps and handoffs that single-screen usability tests can easily miss.

The study of what users must do, in what order, and with what information, to reach a goal. It underpins realistic test tasks and reveals unnecessary steps or missing support.

A fictional but evidence-based description of a representative user type, including goals, skills, and constraints. Personas guide recruitment criteria and help teams judge design decisions from the user's viewpoint.

A user's internal expectation of how a system works and how it should respond. Mismatch between the mental model and the actual design is a frequent source of usability errors.

An action or omission by the user that prevents a task from being completed as intended, or that produces an unintended result. Error rate is a core usability metric.

A defined, repeatable measure of usability such as task success rate, time on task, error count, or satisfaction score. Metrics must be defined before the test to allow comparison across iterations.

The extent to which a product can be used by people with the widest range of abilities, including visual, auditory, motor, and cognitive differences, without unnecessary barriers.

Hardware or software that helps people with disabilities use a product, such as screen readers, magnifiers, switch controls, or speech input. Testing with it reveals barriers invisible in standard sessions.

Software that converts on-screen content into speech or braille, relying on correct semantics and labels. Testing with it exposes missing alternative text, poor heading structure, and unlabelled controls.

A textual substitute for non-text content such as images or charts, conveying equivalent information to users who cannot see it. Missing or meaningless alternative text is a common accessibility defect.

The Web Content Accessibility Guidelines, an internationally referenced standard organised around four principles: perceivable, operable, understandable, and robust, with testable success criteria at three conformance levels.

One of the three WCAG levels, A, AA, or AAA, indicating increasing accessibility requirements. Level AA is the most commonly mandated target in regulation and procurement.

A multi-part international standard on ergonomics of human-system interaction. Its usability definition and guidance on dialogue principles and evaluation methods are widely referenced in test practice.

The likelihood and impact of users being unable to achieve goals effectively, efficiently, or satisfactorily because of a design weakness. Identifying it early guides where testing effort should be concentrated.

Planning usability evaluation so that effort is proportional to identified usability risks, such as high-frequency tasks, safety-relevant actions, or diverse user groups. It prioritises scenarios rather than covering screens evenly.

A rating combining the impact of a usability problem with its frequency and persistence. Severity ranking helps teams decide which findings must be fixed before release and which can be deferred.

A documented observation of a user difficulty, linked to evidence such as video timestamp, task, and participant. Findings should describe the observed problem, not prescribe a solution prematurely.

A reported usability problem that does not reflect a genuine user difficulty, often caused by a biased task, faulty test data, or facilitator influence. It wastes remediation effort and erodes trust in findings.