Glossary

Search results

Pulse Oximetry(also: Pulse Oximeter, SpO2 Monitoring)

A non-invasive method of monitoring blood oxygen saturation (O2sat) and heart rate using a sensor typically placed on the finger or wrist. Pulse oximeters use light absorption through the skin to estimate the percentage of hemoglobin in the blood that is carrying oxygen. In…

Pupil Diameter(also: Pupil Size, Aperture Size)

The width of the opening in the iris through which light enters the eye, typically ranging from about 2mm in bright light to 8mm in darkness. Pupil diameter significantly affects visual quality because it determines how much of the eye's optical aberrations influence the image…

Pupillometry(also: Pupil Dilation Measurement)

A psychophysiological measurement technique that tracks changes in pupil diameter as an objective indicator of cognitive workload, mental effort, and emotional arousal. In accessibility research, pupillometry provides a non-invasive way to assess how demanding an interface or…

Purposive Sampling(also: Purposeful Sampling, Judgment Sampling)

A non-probability sampling method in which researchers deliberately select participants based on specific characteristics relevant to the research questions. In accessibility research, purposive sampling is commonly used to recruit participants with particular disabilities,…

Pursed-lip Breathing(also: PLB)

A breathing technique in which the person inhales gently through the nose and exhales slowly through lightly pursed lips, with the exhalation lasting at least twice as long as the inhalation. The prolonged exhalation against pursed lips creates positive back-pressure in the…

Push-to-Talk(also: PTT, Push to talk)

An interaction pattern where a user presses and holds (or taps) a dedicated button to signal the start of an input — historically used in two-way radios, now common in voice assistants and conversational interfaces as an alternative to continuous listening. In accessibility…

Pusher Syndrome(also: Contraversive Pushing, Lateropulsion)

A clinical disorder occurring in some stroke survivors in which the patient actively pushes their body weight away from the non-paralyzed (non-hemiparetic) side, leading to a severe loss of postural balance. Typically caused by damage to the left or right brain, pusher syndrome…

Put That There(also: Put-That-There)

A pioneering multimodal interactive system built at MIT's Architecture Machine Group (1979-1980), reported by Bolt (1980) and further developed by Schmandt and Hulteen (1982). Users seated in a 'media room' could manipulate a graphical database — such as a Caribbean shipping map…

QR Code(also: Quick Response Code)

A two-dimensional barcode that encodes information such as text, URLs, or other data in a square matrix of black and white modules. In accessibility contexts, QR codes serve as a bridge between physical objects and digital information — they can be placed on tactile graphics to…

QR code accessibility(also: QR code labels, Machine-readable labels)

The use of Quick Response (QR) codes as an alternative to Braille or printed text for encoding information in tactile graphics, product labels, or physical environments that can be read by smartphone cameras. QR codes can encode 45% more text than Braille in the same physical…

QUEST(also: Quebec User Evaluation of Satisfaction with Assistive Technology)

A standardised outcome measure designed to evaluate a person's satisfaction with their assistive technology device and the services related to it. QUEST 2.0 consists of 12 items rated on a five-point satisfaction scale, covering eight device-related items (dimensions, weight,…

QWERTY Keyboard(also: QWERTY)

A QWERTY keyboard is the dominant Latin-script keyboard layout, named for the first six letters on the top row, originally designed for mechanical typewriters and carried forward into computers and mobile devices. On mobile handsets, QWERTY has appeared in both hardware form…

Quadriplegia(also: Tetraplegia)

A condition involving paralysis or significant loss of motor function in all four limbs and the torso, typically resulting from spinal cord injury at the cervical level, neurological disease, or congenital conditions. Quadriplegia profoundly affects how individuals interact with…

Quadriplegia(also: Tetraplegia)

Paralysis affecting all four limbs and typically the torso, usually resulting from spinal cord injury at the cervical (neck) level, or from conditions like ALS or muscular dystrophy. The degree of impairment varies based on the level and completeness of injury—some individuals…

QualWeb(also: QualWeb Evaluator)

An open-source automated web accessibility evaluation tool developed at the University of Lisbon that tests web pages against WCAG success criteria and ACT Rules. QualWeb is notable for being among the first accessibility evaluation tools to incorporate semantic analysis…

Qualitative Coding(also: Thematic Coding, Open Coding, Axial Coding)

A systematic research method for analyzing qualitative data (such as interview transcripts, survey responses, or text outputs) by assigning labels or codes to segments of data that represent meaningful patterns, themes, or concepts. In accessibility research, qualitative coding…

Qualitative Content Analysis(also: QCA)

A systematic qualitative research method for interpreting the content of text, interview transcripts, or other communication data by coding recurring patterns and organizing them into categories. QCA can be inductive (categories emerge from data) or deductive (categories derived…

Qualitative Data Analysis(also: QDA, Qualitative Analysis)

A research methodology for systematically examining non-numerical data such as interview transcripts, field notes, audio recordings, images, and videos to identify patterns, themes, and meanings. The process typically involves coding data segments, categorizing codes into…

Quality Assurance(also: QA)

Systematic processes for ensuring that products or services meet defined standards of quality before reaching end users. In 3D-printed assistive technology programs, quality assurance includes inspecting printed devices for structural integrity, proper dimensions, smooth…

Quality assurance(also: QA)

In accessibility, the process of checking that the methods and practices used to create a product follow established guidelines and best practices. Quality assurance is largely qualitative — it asks whether the right processes were followed, whether accessibility was considered…

Quality control(also: QC)

In accessibility, the process of testing a product or its components against a defined specification to verify conformance. Quality control is quantitative — it measures specific outcomes, such as whether images have alt text, whether colour contrast meets WCAG thresholds, or…

Quality of Communication Life Scale(also: QCL, ASHA QCL)

A self-report assessment developed by ASHA (American Speech-Language-Hearing Association) that measures how communication disorders affect an individual's quality of life. The QCL evaluates domains including socialization, confidence, roles and responsibilities, and independence…

Quality of Life(also: QoL, WHOQOL)

Quality of life (QoL) is a multidimensional construct used in disability, rehabilitation, and accessibility research to capture well-being across physical health, psychological state, social relationships, and environmental factors. The World Health Organization's WHOQOL…

Quality of Life Framework(also: QoL Framework, WHOQOL)

A structured approach to measuring and understanding an individual's overall well-being across multiple domains including physical health, psychological well-being, social relationships, environment, independence, and personal beliefs. The WHO Quality of Life framework (WHOQOL)…

Quality of Life Technology(also: QoLT, QoL Technology)

An umbrella term encompassing technologies designed to maintain or enhance the health, functioning, and independence of older adults and people with disabilities. Quality of life technology includes assistive technology, smart home systems, telemedicine, health monitoring…

Quality of Perception(also: QoP)

An evaluation framework from the multimedia-accessibility research literature for measuring how well a user can understand and use a media presentation, combining objective comprehension metrics (e.g., fact-recall or multiple-choice quiz accuracy) with subjective judgements…

Quantified Self(also: Self-Tracking, Personal Informatics, Lifelogging)

The practice of using technology to systematically track and analyse data about one's own body, health, behaviour, and daily activities. Common tools include fitness trackers, smartwatches, heart rate monitors, and mobile apps that record metrics such as steps, sleep, calories,…

Queer Theory in HCI(also: Queering HCI, Queer Design)

The application of queer theory to human-computer interaction research and design, challenging heteronormative and binary assumptions embedded in technology. Queer theory in HCI questions how technologies enforce normative identities around gender, sexuality, and embodiment, and…

Queer-crip(also: Queer-crip theory, Queer crip)

A theoretical lens combining queer theory and crip theory to examine how queerness and disability co-produce experiences of marginalisation, care, and resistance. Queer-crip perspectives critique compulsory independence, heteronormativity, and ableist temporalities, instead…

QuickDASH(also: Quick Disabilities of the Arm, Shoulder and Hand)

A shortened version of the DASH (Disabilities of the Arm, Shoulder and Hand) outcome measure, consisting of 11 items that assess a person's ability to perform upper extremity activities of daily living. The QuickDASH produces scores from 0 (no disability) to 100 (most severe…

QuickFire(also: Quick Phrases, Quick Response Buttons)

Pre-programmed short phrases or responses stored on AAC devices that can be accessed and played quickly with minimal navigation, typically arranged on a single page for rapid access. QuickFire phrases commonly include backchanneling responses ("yes," "no," "wait"), social…

Quorum(also: Quorum Programming Language)

An evidence-based programming language designed with accessibility as a core principle, making it usable by people with and without visual impairments. Quorum provides audio input and output, screen reader compatibility, and an accessible debugger called SODBeans that uses…

R(also: R Programming Language, R Project, R Statistical Computing)

A free, open-source programming language and software environment widely used for statistical computing, data analysis, and graphical representation. R is the standard tool for statisticians in both academia and industry, offering extensive libraries for creating data…

RACI Matrix(also: RACI chart, Responsibility Assignment Matrix)

A project-management tool that maps tasks to stakeholders using four roles: Responsible (does the work), Accountable (owns the outcome), Consulted (provides input), and Informed (kept in the loop). Accessibility teams use RACI matrices to clarify who within a cross-functional…

RAG(also: Retrieval-Augmented Generation)

An AI architecture pattern that pairs a large language model with an external knowledge store (typically a vector index of text chunks) so that, for each user query, relevant documents are retrieved first and injected into the prompt before the model generates a response. RAG…

RANSAC(also: Random Sample Consensus)

An iterative algorithm (Fischler and Bolles, 1981) for fitting a mathematical model to data that contains a significant proportion of outliers. In accessibility-focused indoor navigation systems, RANSAC is commonly used to detect the floor plane from a LiDAR point cloud — points…

RAVEN(also: Rule-based Accessibility Validation Environment)

An accessibility testing tool developed by IBM as a set of Eclipse IDE plug-ins for verifying the accessibility of graphical user interface applications. RAVEN uses aspect-oriented programming techniques to provide non-invasive, automatic to semi-automatic accessibility…

RDF(also: Resource Description Framework)

A W3C standard for describing resources on the web using a graph-based data model of subject-predicate-object triples. RDF provides a foundation for the Semantic Web by enabling machine-readable metadata that can describe relationships between web resources, including…

REAPER(also: Rapid Environment for Audio Production, Engineering, and Recording)

A digital audio workstation (DAW) software application developed by Cockos that is known for its relatively strong accessibility support compared to other professional DAWs. When used with the OSARA (Open Source Accessibility for the REAPER Application) extension, REAPER…

RESOLV Icons(also: Representational Enumerated Semi-transparent Overlaid Labels for Voice)

A visual disambiguation technique for voice interfaces where semi-transparent numbered labels are overlaid on screen elements that match an ambiguous voice command. When a user speaks a command that could refer to multiple targets, RESOLV icons appear next to each matching…

RFID(also: Radio Frequency Identification, RFID Tag)

A technology that uses electromagnetic fields to automatically identify and track tags attached to objects. RFID tags contain electronically stored information that can be read by RFID readers without line-of-sight contact. In accessibility applications, RFID enables physical…

RGB-Depth Camera(also: RGB-D camera, Depth camera)

A camera that captures both a conventional colour image (RGB) and a per-pixel depth map, usually via structured light, time-of-flight, or stereo sensing. RGB-D cameras are widely used in assistive navigation systems for people who are blind because they enable real-time…

RGBD Camera(also: RGB-D Camera, Depth Camera, Stereo Camera)

A camera that captures both a colour (RGB) image and a per-pixel depth (D) measurement of the scene, yielding a 3D representation of the environment. Depth can be produced by stereo vision, structured light, or time-of-flight sensing. In accessibility research RGBD cameras…

RNIB(also: Royal National Institute of Blind People, Royal National Institute for the Blind)

The largest charity supporting blind and partially sighted people in the United Kingdom, providing services including accessible format transcription, assistive technology advice, employment support, and advocacy. The RNIB operates one of the world's leading music transcription…

RSSI(also: Received Signal Strength Indicator, Received Signal Strength Index)

A measurement of the power level of a radio signal received by a device, commonly used in Bluetooth and Wi-Fi based indoor positioning systems. In accessible indoor navigation, RSSI readings from BLE beacons are used to estimate a user's distance from each beacon — stronger…

RSSI Fingerprinting(also: Received Signal Strength Fingerprinting, Radio Fingerprinting, Signal Fingerprinting)

An indoor localization technique in which a device estimates its position by comparing the current pattern of received signal strengths (RSSI) from surrounding radio sources — most commonly Bluetooth Low Energy beacons or Wi-Fi access points — against a pre-collected map of…

Radial Direction(also: Angular Direction, Heading, Bearing (audio display))

In auditory-display research, a data value that represents a direction in a plane — for example a compass bearing, the tangent of a curve, or the orientation of a pointer — treated as an angle rather than as a pair of Cartesian coordinates. Radial values are inherently circular…

Raised Line Drawing(also: Raised Line Graphic, Tactile Line Drawing, Swell Paper Drawing)

A graphic representation in which lines and shapes are physically raised above the surface of paper or another substrate so they can be perceived by touch. Raised line drawings are a fundamental tool for making visual information accessible to blind and low-vision users,…

Raised-Line Drawing(also: Raised-Line Picture, Tactile Line Drawing, Embossed Line Drawing)

A raised-line drawing is a tactile representation of a visual image created by producing elevated lines on a surface that can be felt by touch, enabling blind and visually impaired people to perceive graphical information through their fingertips. Raised-line drawings can be…

Random Forest Classifier(also: Random Forest)

A machine learning algorithm that creates multiple decision trees during training and outputs the class that is the mode of the individual trees predictions. Random forests are widely used in gesture recognition, activity recognition, and other classification tasks in assistive…