Glossary

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Random Walk(also: Random Walk Sampling)

In web-accessibility evaluation, a random walk is a probabilistic sampling method that starts from a seed page (typically the home page) and follows outgoing links according to a probability rule — for example, with probability d follow a uniformly-chosen outgoing link, and with…

Randomization Test(also: Randomisation Test, Permutation Test)

A randomization test (also called a permutation test) is a non-parametric statistical test that computes a p-value by re-shuffling the observed data many times under the null hypothesis and asking how often the re-shuffled data produce a test statistic as extreme as the one…

Range of Motion(also: ROM)

The full extent of movement possible at a joint, measured in degrees of rotation or linear distance. Range of motion is a fundamental clinical measurement used by occupational and physical therapists to assess hand, wrist, elbow, and shoulder function. In accessibility contexts,…

Range of Motion(also: ROM, Joint Mobility)

The full movement potential of a joint, measured in degrees of a circle, from the starting position to maximum extension or flexion. Range of motion exercises are fundamental to physical rehabilitation, helping maintain joint flexibility and prevent contractures. In…

Rapid Auditory Processing(also: RAP, Auditory Temporal Processing)

The ability to perceive and process rapidly changing auditory signals that occur within tens of milliseconds, such as the rapid frequency and amplitude transitions that characterise speech sounds. Rapid auditory processing is a fundamental skill for language acquisition, as…

Rapid Prototyping

The fast fabrication of a physical model or functional prototype using computer-aided design and manufacturing technologies like 3D printing. In assistive technology development, rapid prototyping enables quick iteration on device designs, allowing makers to test and refine…

Rapid Serial Visual Presentation(also: RSVP)

A text display method in which words or short phrases are shown one at a time in a fixed location on screen in quick succession, eliminating the need for eye movements (saccades) between words. RSVP was first proposed in the 1950s for reading research and adapted for practical…

Ray Casting(also: Raycasting)

An interaction technique in 3-D environments where an invisible ray is projected from a point (such as a user's finger position or controller) into the virtual scene to determine which object the ray intersects first. In VR accessibility, ray casting translates 2-D touch input…

Re-identification risk(also: De-anonymization risk, Data re-identification)

The possibility that an individual can be identified from supposedly anonymized data by combining multiple data points or matching against external datasets. People with disabilities face heightened re-identification risk because uncommon combinations of attributes — rare…

Re-narration(also: Web Re-narration, Content Re-narration)

The process of creating alternative versions of web content — such as translations, simplifications, audio descriptions, or culturally adapted media — to make it accessible to audiences who cannot effectively use the original. Unlike simple translation or metadata repair,…

Re-speaking(also: Respeaking, Speech-to-Text Relay)

A captioning technique in which a trained operator listens to a speaker and repeats (re-speaks) their words clearly into a high-quality microphone in a controlled environment, allowing automatic speech recognition software to generate captions with higher accuracy than direct…

Reach Envelope(also: Workspace Envelope, Reach Zone, Comfort Zone)

The three-dimensional volume of space that a person can physically access with their hands or arms from a given position, taking into account their specific motor abilities, range of motion, and comfort levels. For people with upper extremity mobility impairments — such as those…

Reacher(also: Grabber, Reacher-Grabber, Grabber Tool)

A reacher (also called a grabber or reacher-grabber) is a low-cost handheld assistive device — typically a lightweight aluminum or plastic shaft 60-90 cm long with a trigger handle at one end and a pair of gripping jaws at the other — used by people with limited reach, mobility,…

Reaching Time(also: Navigation Time, Time to Target)

A usability metric measuring the time required for a user to navigate to a specific element on a web page. For blind users employing screen readers, reaching time is a key indicator of page navigability and efficiency, as it captures the cumulative cost of navigating through and…

Read-Along(also: Read Along, Synchronised Highlighting, Karaoke-style Highlighting)

An accessibility pattern in which on-screen text is highlighted word-by-word or phrase-by-phrase in synchronisation with spoken audio. Used in children's reading apps, language-learning tools, accessible ebook formats (e.g., EPUB Media Overlays), and podcast players.…

Read-Aloud Technology(also: Read-Aloud Feature, Text Read-Aloud)

Technology that converts written text to spoken audio output, allowing users to listen to content rather than or in addition to reading it visually. Read-aloud technology differs from general text-to-speech in its focus on synchronized presentation — highlighting words or…

Readability(also: Text Readability)

The ease with which a reader can read and understand written text. Readability encompasses both visual readability (typography, layout, color contrast, spacing) and linguistic readability (vocabulary complexity, sentence structure, text organization). In accessibility contexts,…

Readability(also: Text Readability)

The ease with which written text can be read and understood, determined by factors including vocabulary complexity, sentence length, grammatical structure, and text organisation. Readability is distinct from legibility (which concerns the visual clarity of individual characters…

Readability formula(also: readability metric, readability index, readability measure)

A mathematical formula that estimates the difficulty of reading a text, typically based on features like sentence length, word length, syllable count, or vocabulary frequency. Common formulas include Flesch Reading Ease, Flesch-Kincaid Grade Level, SMOG, and Gunning Fog Index.…

Readily Achievable(also: Readily Achievable Barrier Removal)

A legal concept from the Americans with Disabilities Act (ADA) meaning that barrier removal is easily accomplishable and able to be carried out without much difficulty or expense. What qualifies as readily achievable is measured in context — large, well-resourced organizations…

Reading Assistance(also: Reading Assistance Technology, Reading Support Tools)

Reading assistance refers to technologies and strategies that help people understand written text more easily. This includes tools like text-to-speech, automatic text simplification, screen readers, reading rulers, and dictionary lookups. For accessibility, reading assistance is…

Reading Assistant(also: Reading Aid, Reading Machine)

An assistive technology device or software application that helps people with visual impairments or reading disabilities access printed or displayed text. Reading assistants may use optical character recognition to convert text images to speech, magnification to enlarge text, or…

Reading Comprehension(also: Text Comprehension)

The ability to understand, interpret, and derive meaning from written text. Reading comprehension involves multiple cognitive processes including decoding words, activating background knowledge, making inferences, and monitoring understanding. It is a key target for reading…

Reading Disability(also: Reading Difficulty, Reading Disorder)

A condition that impacts a person's ability to read and develop literacy skills. Reading disabilities encompass a wide range of conditions including dyslexia, alexia, and difficulties arising from intellectual disabilities, cognitive impairments, sensory disabilities, or…

Reading Fluency

The ability to read connected text accurately, at an appropriate pace, and with proper expression - distinct from word-level decoding skill on one side and from reading comprehension on the other. Fluency is typically measured along three dimensions: accuracy (proportion of…

Reading Level(also: Grade Level, Reading Grade Level)

An estimate of the education or skill level a reader needs to understand a text, usually expressed as a U.S. school grade (e.g., grade 4) or an equivalent band. Reading level is the target output of most readability formulas and automatic readability assessment systems, and it…

Reading Literacy(also: Print Literacy, Text Literacy)

The ability to read and comprehend written text. In accessibility research with Deaf and Hard of Hearing populations, reading literacy is an important consideration because English literacy rates are statistically lower among deaf adults in the United States compared to the…

Reading Model(also: Theory of Reading)

A theoretical framework that explains the cognitive processes involved in reading and how reading skills develop. Key reading models include the Simple View of Reading (comprehension = decoding × language comprehension) and the Rope Model (which describes fluent reading as the…

Reading Order(also: Logical Reading Order, Narration Order)

The sequence in which content is presented to assistive technology users, particularly screen reader users, when navigating a document or web page. For sighted users, the visual layout of a document (columns, sections, sidebars) implicitly suggests a reading flow, but screen…

Reading Speed(also: Reading Rate, Words Per Minute)

The pace at which a person can read and process text, typically measured in words per minute. Reading speed is a common metric in evaluating reading support technologies and varies significantly among people with different disabilities. People with dyslexia often experience…

Reading Support Technology(also: Reading Assistive Technology, Reading Aid)

Any technology designed to make reading more accessible for people with disabilities, encompassing tools that support decoding, comprehension, readability, navigation, and literacy development. Reading support technologies range from visual augmentations and text simplification…

Reading accessibility(also: Readable content, Text accessibility)

The design of written content and reading interfaces to be usable by people with diverse literacy levels, cognitive abilities, language backgrounds, and sensory capabilities. Reading accessibility encompasses plain language, text simplification, adjustable typography (font size,…

Real Word Error(also: Real-Word Spelling Error)

A spelling error that results in a correctly spelled but unintended word, such as typing "hear" instead of "here" or "their" instead of "there." Real word errors are particularly common among people with dyslexia and pose a significant challenge because standard spellcheckers…

Real-Time Captioning(also: Live Captioning, Live Transcription)

The process of converting spoken language into text simultaneously as it is being spoken, displayed with minimal delay. Real-time captioning is essential for deaf and hard of hearing individuals to participate in live events, meetings, lectures, and conversations. Methods…

Real-Time Captioning(also: CART, Communication Access Realtime Translation, Live Captioning)

The instant conversion of spoken language into text displayed simultaneously as speech occurs, provided either by a trained human captioner or through automatic speech recognition (ASR) technology. Real-time captioning is a critical accessibility service for Deaf and…

Real-Time Captioning(also: Live Captioning, Real-Time Text)

The process of converting spoken language into text that is displayed simultaneously or near-simultaneously as the speech occurs. Real-time captioning is essential for deaf and hard of hearing individuals to participate in live events, meetings, and educational settings. Methods…

Real-Time Captioning(also: Live Captioning, CART, Communication Access Realtime Translation)

The process of converting spoken language into text display in real time, typically with only a few seconds of delay. Professional real-time captioning (CART) uses stenographers with specialised shorthand keyboards who can type at speaking rates of 170+ words per minute,…

Real-Time Captioning(also: Live Captioning, Live Speech-to-Text)

The process of converting spoken language to text simultaneously or with minimal delay as the speech occurs. Real-time captioning can be produced by human transcriptionists (CART, C-Print, TypeWell), crowd workers, automatic speech recognition (ASR), or hybrid approaches. Unlike…

Reasonable Accommodation(also: Workplace Accommodation, Job Accommodation)

A modification or adjustment to a job, work environment, or the way work is typically performed that enables a qualified individual with a disability to perform essential job functions and enjoy equal employment opportunities. Under the Americans with Disabilities Act (ADA) and…

Reasonable accommodation(also: Reasonable adjustment, Workplace accommodation)

A modification or adjustment to a job, work environment, or workplace process that enables an employee with a disability to perform essential job functions and enjoy equal employment opportunities. Reasonable accommodations can include flexible work hours, quiet workspaces,…

Reassurance Robot

A term coined by Grace Barkhuff (CHI 2026) to describe generative AI systems — such as ChatGPT — that, by default, provide reassurance, confession-hearing, and decision-making on demand, thereby accommodating the compulsions of people with Obsessive-Compulsive Disorder (OCD).…

Reassurance Seeking(also: Reassurance-Seeking Behavior)

A compulsive behavior in OCD where individuals repeatedly seek confirmation from others (or from technology, such as internet searches) that feared outcomes have not occurred or will not occur. Reassurance seeking provides temporary anxiety relief but reinforces the…

Receptive and Expressive Skills(also: Receptive Signing, Expressive Signing, Receptive Skills)

In language learning, receptive skills are the ability to understand a language — reading and listening in spoken languages, watching and comprehending signing in sign languages — while expressive skills are the ability to produce the language. For sign-language learners,…

Recipe Progress Tracking(also: Cooking Progress Monitoring)

The specific application of procedural task tracking to cooking, where a system monitors which recipe steps have been completed and what remains. For BLV cooks, recipe progress tracking addresses a critical gap: existing voice-based recipe tools can read steps but cannot verify…

Reciprocity(also: Conversational Reciprocity, Social Reciprocity)

The back-and-forth exchange of information, questions, and responses that characterizes natural conversation. Reciprocity includes components like asking questions, responding appropriately, giving feedback, and sharing information in ways that maintain conversational flow.…

Recognition-Based Authentication(also: Cognometric Authentication)

A type of graphical authentication where users authenticate by recognizing and selecting previously registered images from a set that includes decoy images. Unlike recall-based systems that require users to remember and reproduce a pattern, recognition-based systems leverage the…

Recreational Accessibility(also: Leisure Accessibility)

The design and provision of recreational activities, spaces, and experiences that are inclusive of people with disabilities. Recreational accessibility extends beyond basic physical access to encompass independent participation in leisure pursuits such as shopping, tourism,…

Recreational Exploration(also: Wandering exploration, Exploratory navigation, Open-ended exploration)

Movement through an environment driven by interest, curiosity, or enjoyment rather than by a fixed destination — for example wandering a museum, browsing a shopping mall, or exploring a neighbourhood. For blind and low-vision people, recreational exploration is harder to support…

Recurrent Neural Network(also: RNN)

A recurrent neural network (RNN) is a type of artificial neural network designed to process sequential data by maintaining an internal state (memory) that captures information from previous inputs in the sequence. Unlike feedforward networks, RNNs have connections that loop…

Red Teaming(also: Generative Red-Teaming, AI Red Teaming)

A structured evaluation practice in which an adversarial team probes a system — traditionally a network or application, increasingly an AI model or conversational agent — with realistic attack scenarios to find failures before malicious actors do. Generative red-teaming…