Glossary

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Landmark Detection(also: Acoustic Landmark Detection, Stevens Landmark Theory)

Landmark detection is a speech analysis method based on Kenneth Stevens' acoustic model of speech production, which identifies perceptually significant points in the acoustic signal where listeners extract information about underlying distinctive features. Three primary landmark…

Latin Square Design(also: Latin Square Counterbalancing)

A counterbalancing method used in experimental research to control for order and sequence effects when each participant experiences multiple conditions. In a Latin Square arrangement, conditions are ordered so that each condition appears in each position (first, second, third,…

Levenshtein Distance(also: Edit Distance)

A metric that measures the minimum number of single-character edits (insertions, deletions, and substitutions) needed to transform one string into another. In accessibility research, Levenshtein distance is used to quantify how much users modify AI-generated or existing text,…

Librosa

An open-source Python library for audio and music signal analysis, widely used in music-information retrieval and accessibility research to extract low-level acoustic features such as tempo, RMS energy, spectral centroid, zero-crossing rate, chroma, and mel-frequency cepstral…

Likert Scale(also: Likert-Type Scale)

A psychometric rating scale commonly used in surveys and usability studies where respondents indicate their level of agreement or satisfaction on a symmetric scale, typically with 5 or 7 points ranging from "strongly disagree" to "strongly agree." Likert scales are standard…

Low-Fidelity Prototype(also: Low-Fi Prototype, Lo-Fi Prototype, Paper Prototype)

A rough, inexpensive representation of a design - typically paper sketches, cardboard models, or wireframes - used early in the design process to explore concepts without investing in polished artefacts. Low-fidelity prototypes lower the barrier to critique and change, which is…

Low-Fidelity Prototyping(also: Lo-Fi Prototyping, Paper Prototyping)

A design method that uses simple, inexpensive materials to create quick, rough representations of a product or interface for early-stage testing and feedback. Traditional lo-fi prototyping relies heavily on visual methods such as sketches, storyboards, and paper mockups, which…

Low-Incidence Disability(also: Low-Prevalence Disability)

A disability that occurs relatively rarely in the general population, such as blindness, deafblindness, or certain developmental conditions. Low-incidence disabilities present unique challenges for research, education, and technology development because affected individuals are…

Lubben Social Network Scale(also: LSNS, LSNS-6)

A validated screening instrument used to assess social isolation risk in older adults by measuring the size and closeness of their social networks. The abbreviated LSNS-6 version contains six items covering family and friend networks, asking about the number of relatives and…

Matching Person and Technology(also: MPT Model)

A framework for understanding assistive technology adoption that considers the match between a person's characteristics (preferences, needs, lifestyle), the environmental context, and the technology's features. Developed by Marcia Scherer, the MPT model frames AT adoption as a…

Mean Power Frequency(also: MPF, Mean Frequency)

Mean power frequency is a single-number summary of a signal's frequency content, computed as the power-spectrum-weighted mean of frequency. In surface-EMG-based accessibility input devices, MPF of each electrode channel is used to discriminate between contractions of nearby…

Mediated Communication(also: Proxy Communication, Supported Communication)

Communication that is facilitated or interpreted through a third party, such as a caregiver, support worker, family member, or communication partner who knows the person well. In research involving people with intellectual disabilities or complex communication needs, mediated…

Member Checking(also: Respondent Validation, Participant Validation)

A qualitative research technique in which researchers share their data interpretations and findings with members of the studied community to assess accuracy, resonance, and completeness. Member checking enhances the validity of qualitative research by ensuring that the…

Mental Fatigue(also: Cognitive Fatigue, Mental Exhaustion)

A state of reduced cognitive capacity resulting from prolonged mental effort, characterized by difficulty concentrating, slower processing, increased errors, and reduced ability to handle unexpected situations. Mental fatigue particularly affects people with dementia, traumatic…

Meta-Research(also: Research on research, Metascience)

The systematic study of research itself — the tools, workflows, norms, infrastructures, and institutional practices through which scholarly knowledge is produced, evaluated, and disseminated. Meta-research examines questions such as which methods and technologies researchers…

Minimum Clinically Important Difference(also: MCID, Minimal Clinically Important Difference)

The smallest change in a measurement that is perceived as beneficial or meaningful from a clinical perspective. MCID thresholds help researchers and clinicians distinguish statistically significant changes from clinically meaningful improvements. In digital health and assistive…

Minimum String Distance(also: MSD, Edit Distance, Levenshtein Distance)

A metric for measuring text entry accuracy by calculating the minimum number of single-character insertions, deletions, and substitutions needed to transform the transcribed text into the intended text. In text entry research, the MSD error rate is typically expressed as a…

Mixed Methods Research(also: Mixed-Methods, Multi-Method Research)

A research approach that combines quantitative methods (statistical analysis, surveys, measurements) with qualitative methods (interviews, thematic analysis, ethnography) within a single study or program of research. Mixed methods research is common in accessibility studies…

Mixed Methods Research(also: Mixed Methods, Mixed Method Evaluation)

A research approach that combines both quantitative methods (such as performance measurement and statistical analysis) and qualitative methods (such as interviews and thematic analysis) within a single study. In accessibility research, mixed methods are particularly valuable…

N-back Task(also: N-back, 2-back Task)

A working-memory paradigm in which participants view or hear a sequence of stimuli (letters, digits, positions) and, on each trial, respond when the current stimulus matches the one presented N steps earlier. Higher N levels place greater load on working memory and executive…

NASA Task Load Index(also: NASA-TLX, Task Load Index)

A widely used subjective workload assessment tool developed by NASA that measures perceived workload across six dimensions: mental demand, physical demand, temporal demand, performance, effort, and frustration. Participants rate each dimension on a scale, providing a…

NASA Task Load Index(also: NASA-TLX, TLX)

A widely used subjective workload assessment tool developed by NASA that measures perceived workload across six dimensions: mental demand, physical demand, temporal demand, performance, effort, and frustration. In accessibility research, NASA-TLX is frequently employed to…

NASA-TLX(also: NASA Task Load Index, Task Load Index, NASA TLX)

A widely used subjective workload assessment tool developed by NASA that measures perceived workload across six dimensions: mental demand, physical demand, temporal demand, performance, effort, and frustration. In accessibility research, NASA-TLX is frequently used to evaluate…

Narrative-Flip Method(also: Narrative flip)

A qualitative HCI research method in which participants first encounter a technology or artifact without knowing its origins or intent, reflect on it, and only afterwards are told its disability-led, activist, or political context. The deliberate before/after framing surfaces…

Native Signer(also: Native Sign Language User, L1 Signer)

A person who acquired a sign language as their first language (L1) during the critical period of language development, typically before age 5. Native signers usually learned sign language from deaf parents or through early immersion in deaf education environments. In…

Need-Finding Interview(also: Need-Finding Study, Needs Assessment Interview)

A qualitative research method conducted early in the design process to understand users' current practices, challenges, unmet needs, and desires for future solutions. Need-finding interviews typically use open-ended questions and semi-structured formats to elicit rich…

Networked Minds Social Presence Inventory(also: Networked Minds Measure of Social Presence, NMSPI)

The Networked Minds Social Presence Inventory is a self-report questionnaire developed by Biocca, Harms and colleagues to measure social presence - the sense of 'being together' with another person - in mediated environments such as video calls, virtual reality or augmented…

Non-Use(also: Technology Non-Use, Technology Refusal)

A research tradition in HCI that takes seriously the choice not to use a technology — treating refusal, abandonment, and selective engagement as meaningful, reasoned behaviour rather than as failure. Non-use scholarship (Wyatt, Baumer, Satchell & Dourish, Waycott and colleagues)…

Normal-Hearing Listener(also: NH Listener, Normal Hearing)

A research term for a participant whose audiometric thresholds fall within the clinical normal range (typically pure-tone thresholds of 25 dB HL or better across speech frequencies), used as a comparison group in hearing-accessibility studies. Normal-hearing (NH) listeners are…

Novelty Effect(also: Novelty bias)

A research-methodology concept describing the tendency for users to behave differently with a new technology simply because it is new, rather than because of its enduring value. Novelty effects inflate short-term engagement, enthusiasm, and usage, then fade as the technology…

OLAP(also: On-line Analytical Processing, Online Analytical Processing, Data Cube)

OLAP (on-line analytical processing) is a class of database technology that organises data into multi-dimensional 'cubes' — for example, sensor-firing counts indexed by room, time zone, day of week, and week number — and provides fast interactive slice, dice, drill-down, and…

Observational Study(also: Field Observation, Naturalistic Observation)

A research method in which investigators systematically watch and record behaviors, interactions, and practices in a natural setting without manipulating variables or conditions. In accessibility research, observational studies are used to understand how people with disabilities…

Online Focus Group(also: Virtual Focus Group, Remote Focus Group)

A qualitative research method in which a group of participants discusses a topic through an online platform rather than meeting in person. Online focus groups are particularly valuable for accessibility research because they remove physical barriers — such as transportation,…

Operant Conditioning(also: Instrumental Conditioning, Operant Learning)

A learning process in which behaviour is modified by its consequences — specifically, by reinforcement (rewards that increase the likelihood of the behaviour) or punishment (consequences that decrease it). In accessibility research and clinical assessment, operant conditioning…

PICTIVE(also: Plastic Interface for Collaborative Technology Initiatives through Video Exploration)

PICTIVE is a participatory paper-prototyping technique introduced by Michael Muller at CHI 1991, in which end users and designers jointly build low-fidelity interface prototypes using pre-cut paper UI elements (buttons, menus, text fields, icons), sticky notes, pens, and tape,…

POMDP(also: Partially Observable Markov Decision Process)

A Partially Observable Markov Decision Process (POMDP) is a mathematical framework for modelling decision-making in situations where an agent cannot fully observe the state of its environment. In accessibility research, POMDPs are used to model how people with visual impairments…

PRISMA(also: Preferred Reporting Items for Systematic Reviews and Meta-Analyses)

A standardized methodology and reporting guideline for conducting systematic literature reviews and meta-analyses. PRISMA provides a structured framework including a checklist and flow diagram that documents how studies are identified, screened, assessed for eligibility, and…

PRISMA-ScR(also: PRISMA Extension for Scoping Reviews)

PRISMA-ScR is the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews - a 20-item checklist and flow diagram that standardises how scoping reviews are reported. It adapts the PRISMA framework (designed for systematic reviews) to the…

Part-of-Speech Tagging(also: POS Tagging, Grammatical Tagging)

Part-of-speech tagging is the natural-language-processing task of labelling each word in a text with its grammatical category — noun, verb, adjective, and so on — using context from surrounding words. Classical approaches use hidden Markov models with the Viterbi algorithm;…

Participant Recruitment(also: Research Recruitment, Subject Recruitment)

The process of identifying, inviting, and enrolling individuals to participate in research studies. In accessibility research, participant recruitment presents unique challenges including ensuring intersectional representation of disability communities, avoiding overburdening…

Participant Verification(also: Eligibility Verification, Screening Verification)

The process of confirming that research participants genuinely meet a study's eligibility criteria, particularly regarding disability status. Verification is complicated by multiple factors: different models of disability define disability differently; online and remote…

Participant pool(also: User pool, Research panel, Participant registry)

A pre-established database of individuals who have expressed willingness to participate in research studies, maintained with demographic information, contact details, and often cognitive or ability assessments. In accessibility research, dedicated participant pools address the…

Participant pool bias(also: Sampling bias, Recruitment bias)

Systematic distortion in research findings caused by the demographic characteristics and backgrounds of study participants, rather than by the technology or intervention being evaluated. In accessibility research, participant pool bias is especially consequential because…

Participant-led research(also: User-led research)

A research methodology in which participants — particularly those from marginalized or underrepresented groups — take an active role in directing the research process, shaping study protocols, and determining what aspects of a system or experience are most important to…

Participatory Design(also: PD, Cooperative Design, Scandinavian Design)

A design approach originating in Scandinavian workplace democracy movements that emphasizes the direct involvement of people in the design of technologies and systems that affect them. Participatory design treats users as experts in their own experiences and gives them genuine…

Participatory Evaluation(also: PE)

A research approach in which the people affected by a program, technology, or intervention are actively involved in evaluating it, rather than being passive subjects of assessment. In accessibility research, participatory evaluation means disabled people help define evaluation…

Participatory Research(also: Participatory Design Research, Participatory Action Research)

Research methodologies that actively involve the communities being studied as partners in the research process, from defining research questions to collecting data to interpreting findings. In accessibility research, participatory approaches are essential for ensuring that…

Perceptual Analysis(also: Perceptual Judgment, Auditory-Perceptual Analysis)

A method of evaluating speech, voice, or other sounds based on a human listener's subjective auditory impressions rather than instrumental measurement. In clinical speech-language pathology, perceptual analysis is used to categorize vocalizations, rate voice quality, or assess…

Perceptual Learning(also: Visual Perceptual Learning, PL)

A long-studied phenomenon in vision science in which repeated exposure to, or training on, specific perceptual features — color, orientation, spatial location, shape — produces durable improvements in a person’s ability to detect and discriminate those features. Perceptual…

Persona Design(also: Design Personas, User Personas)

A user-centered design technique in which designers create fictional but grounded profiles of representative users — demographics, goals, context, pain points — to guide design decisions when direct user involvement is limited. In accessibility and HCI co-design workshops,…