Glossary

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SUMI(also: Software Usability Measurement Inventory)

A standardised questionnaire-based method for measuring software usability from the end user perspective. SUMI assesses five dimensions: efficiency, affect (user satisfaction), helpfulness, control, and learnability. In accessibility contexts, SUMI can be adapted alongside…

SUS(also: System Usability Scale)

Abbreviation for System Usability Scale, a ten-item questionnaire developed by John Brooke in 1986 that produces a single usability score from 0 to 100 based on user ratings of agreement with statements about a system. SUS is widely used in accessibility and HCI research because…

Social Acceptability(also: Social Acceptance, Technology Stigma)

The degree to which the use of an assistive technology or interaction technique is perceived as socially appropriate by both the user and those around them. Social acceptability is a critical but often underestimated factor in assistive technology adoption. Users may reject…

Social usability

The degree to which a technology supports positive social interactions and self-presentation for its users, particularly in contexts where technology use is visible to others. Social usability goes beyond functional task completion to consider whether using a product causes…

Speech Repair(also: Self-Correction, Speech Self-Repair, Command Correction)

Speech repair is the process of correcting or modifying a spoken utterance after it has been produced, either within the same turn or in a subsequent one. In natural conversation, speakers commonly interrupt themselves to fix errors, change wording, or update information using…

Summative Evaluation(also: Summative Usability Testing, Summative Assessment)

Usability evaluation conducted on functional software or high-fidelity prototypes, typically later in the development process, to measure the effectiveness of specific design choices. Summative testing uses representative users performing representative tasks and often involves…

Target Selection(also: Target Acquisition, Pointing)

The fundamental interaction task of moving a cursor or pointer to a specific location on screen and confirming selection, such as clicking a button or link. Target selection difficulty is affected by target size, distance to target, and user motor abilities—relationships…

Task-Technology Fit(also: TTF)

A concept from information systems research describing how well a technology's capabilities match the requirements of the tasks it is used to perform. In assistive technology, task-technology fit is critical to successful adoption: a mismatch between the type of assistive device…

Technology acceptance(also: User acceptance, Technology adoption)

The degree to which individuals are willing to embrace, use, and integrate a new technology into their practices, influenced by perceived usefulness, ease of use, social norms, trust, and prior experience. In accessibility contexts, technology acceptance is shaped by additional…

Text Correction(also: Text Editing, Error Correction)

The process of identifying and fixing errors in text, including substituting incorrect words, inserting missing content, and deleting extraneous characters or words. For blind users, text correction on mobile devices is significantly more challenging than text entry, as it…

Think Aloud Protocol(also: Think-Aloud Method, Verbal Protocol Analysis, Thinking Aloud)

A usability testing method in which participants verbalize their thoughts, feelings, and decision-making processes while performing tasks with a system or interface. Developed for cognitive interface design research, the think aloud protocol helps evaluators understand how users…

Think-Aloud(also: Think-Aloud Protocol, Verbal Protocol Analysis)

A research method in usability and accessibility testing where participants verbalize their thoughts, strategies, and reactions while performing tasks. Think-aloud protocols are particularly valuable in accessibility research because they reveal the cognitive strategies and…

Think-Aloud Protocol(also: Think Aloud, Verbal Protocol Analysis)

A usability research method in which participants verbalize their thoughts, reactions, and decision-making processes while interacting with a system or performing a task. Think-aloud protocols provide rich qualitative data about user experience, revealing cognitive processes,…

Universal Usability

An approach to technology design that aims to make systems usable by the widest possible range of people, including children, older adults, people with various impairments, people engaged in other tasks, and users with differing levels of education, literacy, and socio-economic…

Usability(also: Ease of Use)

Usability is the extent to which a product, system, or service can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use, as defined by ISO 9241-11. It goes beyond mere accessibility compliance to…

Usability Barrier

A type of access barrier where a task can technically be completed but not with the desired qualities such as speed, ease, accuracy, or comfort. Unlike failure point barriers, the task is possible, but the experience of completing it is unsatisfactory. For example, a web page…

Usability Engineering

A systematic, structured approach to designing and evaluating user interfaces that applies engineering principles to usability. Usability engineering involves defining measurable usability goals, conducting user analysis, iterative prototyping, and empirical testing with…

Usability Heuristics(also: Nielsen's Heuristics, Nielsen Heuristics, 10 Usability Heuristics)

A set of ten general principles for user interface design developed by Jakob Nielsen (originally with Rolf Molich in 1990, refined in 1994): visibility of system status, match between system and the real world, user control and freedom, consistency and standards, error…

Usable Accessibility

Usable accessibility is the principle that meeting technical accessibility standards (such as WCAG compliance) is necessary but not sufficient for ensuring that people with disabilities can effectively use digital products. A website may be technically accessible — screen…

User Engagement Scale(also: UES, UES-SF)

A validated self-report questionnaire for measuring user engagement with digital systems across dimensions including focused attention, perceived usability, aesthetic appeal, and reward. Developed by O'Brien and Toms and later shortened to the 12-item UES Short Form (UES-SF),…

User Experience(also: UX)

A person's perceptions and responses resulting from the use or anticipated use of a product, system, or service, encompassing emotions, beliefs, preferences, physical and psychological responses, and behaviours. Defined by ISO 9241-210, user experience goes beyond usability…

User Experience Questionnaire(also: UEQ, UEQ-S, Short UEQ)

A standardised self-report instrument, developed by Schrepp and colleagues, that captures a user's subjective impression of a product across dimensions such as attractiveness, efficiency, perspicuity, dependability, stimulation, and novelty via pairs of contrasting adjectives…

User Research(also: UX Research, Usability Research)

The systematic study of users and their needs, behaviours, and experiences to inform the design and development of products and services. User research methods include interviews, surveys, focus groups, usability testing, diary studies, contextual inquiry, and beta testing. In…

Viewability(also: Video Viewability)

A subjective measure of how watchable and consumable a video is for a particular viewer, encompassing factors like ability to focus on content, level of distraction, information comprehension, and overall comfort with the viewing experience. In ADHD accessibility research,…

Visual Distraction(also: Visual Clutter, Visual Noise)

Visual elements in an interface or content that draw attention away from the primary content or task, including animated advertisements, moving backgrounds, decorative overlays, notification badges, recommended content panels, and complex visual layouts. Visual distractions are…

Voice Usability(also: Auditory Usability, Non-Visual Web Usability)

The degree to which a web page, application, or document is usable when accessed through a voice browser or screen reader — the audio-first counterpart to traditional visual usability. Voice usability combines structural quality (navigability — how quickly a user can reach…

Web Clutter(also: Page Clutter, Visual Clutter)

Non-essential elements on a web page that do not contribute to the primary content or user task, such as advertisements, decorative images, redundant navigation, social media widgets, and promotional banners. Web clutter disproportionately affects users of assistive…

Web disorientation(also: Lost in hyperspace, Navigation disorientation)

The feeling of being lost or confused while navigating websites, characterized by difficulty knowing one's current location within a site, how to return to previously visited pages, or how to find desired information. Web disorientation is predicted by Internet confidence and…

Wizard-of-Oz(also: WOZ, Wizard of Oz Method, WOZ Study)

A research methodology where participants interact with what they believe is an autonomous system, but a human "wizard" is secretly operating it behind the scenes. Named after the 1939 film, this technique is commonly used in accessibility and HCI research to test interface…

Workaround(also: Hack, Alternative Strategy)

A method or technique used to bypass or overcome a limitation, barrier, or deficiency in a system, particularly when the intended functionality is inaccessible or broken. In accessibility, workarounds are strategies that disabled users develop to accomplish tasks when software…