Accessible Learning Labs · Accessibility

Glossary

Fifty-seven terms used across these resources, defined once so that every other page can link rather than re-explain.

Who this is for. Learning designers, faculty, and readers of the accessibility and Universal Design for Learning resources on this site. Where a term carries an argument beyond its definition, the entry links to the resource that sets it out.

Sources. Each definition cites legislation, case law, a standards-body publication, or scholarly work. The full list is in Sources.

Scope. The entries under Rights, duty and accommodation describe Canadian law as decided. They are not legal advice, and they do not determine whether any obligation applies to any particular organisation or person. Decisions in individual cases rest with accessibility advisors, accommodation offices, and legal counsel.

Another format. This is the linear version. An interactive version adds a search field and group filters. The content of the two files is identical.

11 terms

Models of disability

Frameworks for explaining disability. Each carries different implications for design, policy and the allocation of responsibility.

Medical model

Disability understood as a condition located in the individual body, caused by disease, injury or a health condition, and addressed through treatment, cure or rehabilitation.

The model addresses biological causes and supports clinical management. Its limitation for design work is that it locates the problem in the person rather than in the environment, so an inaccessible building is treated as a consequence of an individual's impairment.

See alsoSocial modelInteraction modelBiopsychosocial model

SourceIAAP, CPACC Body of Knowledge (2023); Retief & Letšosa (2018).

Social model

Disability understood as the product of environments, attitudes and policies built around a narrow range of bodies and minds. Impairment is distinguished from disability, which is what results when that impairment is not accounted for.

The model was formulated in British disability activism and given its academic statement by Michael Oliver. It identifies the barrier as the object of change, which is the premise of accessibility practice. Tom Shakespeare's principal criticism is that strong formulations separate disability from the body entirely, and so omit the effects of impairment itself.

See alsoMedical modelInteraction modelBarrierAbleism

SourceOliver (1990); Shakespeare (2013); Retief & Letšosa (2018).

Interaction model

Disability understood as arising in the meeting between a person's characteristics and a specific environment or task.

The model treats the environment as a variable while retaining the effects of impairment. It accounts for the observation that the same person may encounter barriers in one setting and not in another.

See alsoSocial modelMedical modelBiopsychosocial modelBarrier

SourceIAAP, CPACC Body of Knowledge (2023); WHO, ICF (2001).

Biopsychosocial model

An account treating biological, psychological and social factors as jointly necessary to understand a person's situation. George Engel articulated it in 1977, and it is the conceptual basis of the World Health Organization's ICF.

It is applied in rehabilitation and in settings where clinical and social explanations are both required. It has been criticised for diluting the political claim of the social model, and for a classification complex enough to complicate implementation.

See alsoICFInteraction modelMedical model

SourceWHO, ICF (2001); IAAP, CPACC Body of Knowledge (2023).

ICF

The International Classification of Functioning, Disability and Health, published by the World Health Organization in 2001. It provides a standard vocabulary describing functioning across body functions and structures, activities and participation, with environmental and personal factors as context.

It treats disability as an umbrella term covering impairments, activity limitations and participation restrictions. Functioning is described in relation to a context rather than as a fixed property of a person.

See alsoBiopsychosocial modelFunctional limitationInteraction model

SourceWHO, ICF (2001).

Human rights model

Disability understood as a ground on which people hold enforceable rights that states are obliged to secure. Its principal instrument is the UN Convention on the Rights of Persons with Disabilities.

It differs from the social model in the direction of obligation. The social model identifies a barrier as a design failure; the human rights model assigns responsibility for removing it.

See alsoSocial modelDuty to accommodateNothing about us without us

SourceCRPD (2006).

Charity model

Disability understood as misfortune calling for compassion, with disabled people positioned as recipients of goodwill.

The model can mobilise resources. It positions disabled people as objects of pity rather than holders of rights, addresses immediate need rather than structural change, and makes access contingent on the goodwill of others.

See alsoEconomic modelHuman rights modelAbleism

SourceIAAP, CPACC Body of Knowledge (2023).

Economic model

Disability defined by reduced capacity to work, and assessed by its cost to the individual, the employer and the state.

It underpins disability benefit systems. It measures a person by productivity, and its assessments generally require applicants to demonstrate incapacity in order to receive support.

See alsoCharity modelMedical model

SourceIAAP, CPACC Body of Knowledge (2023).

Ableism

The system of assumptions, practices and institutional arrangements treating a particular range of bodies and minds as the default, and those outside it as deficient.

Jay Dolmage locates ableism in the architecture and routine practices of higher education rather than in individual prejudice. Tanya Titchkosky examines how institutional language frames access as exceptional rather than expected.

See alsoSocial modelBarrierDisability justice

SourceDolmage (2017); Titchkosky (2011).

Disability justice

A framework developed by disabled people of colour and by queer and trans disabled organisers, principally through the collective Sins Invalid, in response to the limits of a disability rights movement organised around legal access.

Its stated principles include intersectionality, leadership of those most impacted, anti-capitalist politics, cross-movement solidarity, interdependence, collective access and collective liberation.

See alsoNothing about us without usAbleismSocial model

SourceSins Invalid (2019); Kafer (2013).

Nothing about us without us

The principle that decisions affecting disabled people require the participation of disabled people. It was formulated as a movement slogan and given book-length treatment by James Charlton in 1998. The CRPD carries a corresponding obligation to consult persons with disabilities through their representative organisations.

Applied to design practice, it sets a threshold: consultation conducted after a decision has been reached does not meet it.

See alsoDisability justiceHuman rights model

SourceCharlton (1998); CRPD (2006).

12 terms

Rights, duty and accommodation

Terms from Canadian human rights law. Each carries a legal meaning distinct from its ordinary usage.

Duty to accommodate

The obligation under human rights legislation to adjust a rule, standard or practice so that it does not discriminate on a protected ground, up to the point of undue hardship.

In British Columbia it arises under the Human Rights Code, which covers employment at section 13 and services customarily available to the public at section 8. Education is a service under section 8, the provision at issue in Moore. The Supreme Court has described accommodation as a multi-party inquiry in which the person requesting it, the employer or institution, and any union each carry responsibilities.

See alsoUndue hardshipProcedural and substantive dutyAccommodationMeiorin test

SourceHuman Rights Code (BC), RSBC 1996, c 210; Renaud, [1992] 2 SCR 970; Moore, 2012 SCC 61.

Procedural and substantive duty

Two components of the duty to accommodate. The substantive duty concerns the outcome: whether a workable accommodation was provided. The procedural duty concerns the process: whether the individual's circumstances were investigated and options canvassed before a conclusion was reached.

An institution can fail the procedural duty in a case where no accommodation would have been possible, because reaching a conclusion without inquiry is itself a breach.

See alsoDuty to accommodateUndue hardshipInteractive process

SourceMeiorin, [1999] 3 SCR 3; Renaud, [1992] 2 SCR 970.

Undue hardship

The threshold at which the duty to accommodate ends. It is distinct from inconvenience, expense or difficulty.

In Renaud, Sopinka J stated that the word undue implies that some hardship is acceptable, and that only undue hardship satisfies the test. The factors identified in Central Alberta Dairy Pool include financial cost, interchangeability of workforce and facilities, and effects on the rights of other employees. Meiorin sets out further lines of inquiry, including whether alternative approaches were investigated and whether the standard could be made less discriminatory while still serving its purpose.

Hardship is established on evidence rather than on impression or anecdote, and cost is assessed against the resources of the organisation as a whole.

See alsoDuty to accommodateMeiorin testBona fide occupational requirement

SourceRenaud, [1992] 2 SCR 970; Central Alberta Dairy Pool, [1990] 2 SCR 489; Meiorin, [1999] 3 SCR 3.

Bona fide occupational requirement

A defence to a discrimination claim in employment. A standard that excludes a person is upheld where the employer meets the three-part test set out in Meiorin.

The corresponding defence outside employment is a bona fide and reasonable justification. Grismer confirmed that it is assessed on the same test.

See alsoMeiorin testEssential requirementUndue hardship

SourceMeiorin, [1999] 3 SCR 3; Grismer, [1999] 3 SCR 868.

Meiorin test

The unified three-part test from British Columbia (Public Service Employee Relations Commission) v BCGSEU (1999). To justify a discriminatory standard, the employer must establish that it was adopted for a purpose rationally connected to the performance of the job; that it was adopted in an honest and good faith belief that it was necessary to that purpose; and that it is reasonably necessary, which requires demonstrating that the individual cannot be accommodated without undue hardship.

The case concerned Tawney Meiorin, a forest firefighter dismissed for failing an aerobic standard that disproportionately excluded women. The decision replaced the earlier distinction between direct and adverse effect discrimination with a single analysis; McLachlin J observed that maintaining the distinction could serve to legitimise systemic discrimination. Grismer extended the test beyond employment later the same year.

See alsoBona fide occupational requirementUndue hardshipAdverse effect discriminationEssential requirement

SourceMeiorin, [1999] 3 SCR 3; Grismer, [1999] 3 SCR 868.

Adverse effect discrimination

Discrimination produced by a rule that is neutral on its face and excludes a protected group in operation.

Since Meiorin the analysis no longer turns on whether discrimination is direct or adverse in form. McLachlin J noted that few rules are framed in overtly discriminatory terms, so the question is generally whether the claimant suffered an adverse effect.

See alsoMeiorin testBarrierConstruct-irrelevant variance

SourceMeiorin, [1999] 3 SCR 3; Moore, 2012 SCC 61.

Essential requirement

What a course, program or credential requires a learner to demonstrate, stated in advance and independently of any particular means of demonstrating it.

The operative distinction is between a competency and its customary mode of expression. Where the outcome is the analysis of a text, reading it in print is a method. Where the outcome is the performance of a clinical procedure, the mode may itself form part of the requirement.

Requirements articulated only after a request has been received are difficult to sustain under the first two steps of the Meiorin test, which ask whether the standard was adopted for a legitimate purpose and in good faith.

See alsoBona fide occupational requirementMeiorin testConstructModification

SourceMeiorin, [1999] 3 SCR 3; AERA, APA & NCME (2014); Moore, 2012 SCC 61.

Accommodation

An adjustment to a rule, practice, environment or format that removes a barrier for an individual while leaving the essential requirement intact.

Universal design reduces the frequency with which accommodation is required. It does not displace the legal duty, since no design anticipates every individual.

See alsoModificationDuty to accommodateUniversal Design for LearningEssential requirement

SourceHuman Rights Code (BC), RSBC 1996, c 210; Renaud, [1992] 2 SCR 970.

Modification

A change that alters what is taught or assessed, rather than how a learner reaches or demonstrates it.

The boundary between accommodation and modification follows the boundary around essential requirements, and cannot be located until those requirements are articulated. In institutional practice the determination rests with accessibility advisors, accommodation offices and academic decision-makers.

See alsoAccommodationEssential requirementConstruct

SourceAERA, APA & NCME (2014).

Functional limitation

A description of what a person can and cannot do in a given context, expressed in terms of function rather than diagnosis. Difficulty sustaining attention for ninety minutes is a functional description; a diagnostic label is not.

Accommodation reasoning proceeds from function. A diagnosis is generally not the information an institution requires, and the same diagnosis produces different functional profiles in different people.

See alsoICFDisclosureInteractive process

SourceWHO, ICF (2001).

Interactive process

The exchange in which an institution and an individual identify a barrier, canvass possible adjustments and settle on one.

The procedural duty is substantially a duty to conduct this exchange. Omitting it constitutes a breach distinct from failing to provide an accommodation.

See alsoProcedural and substantive dutyDuty to accommodateFunctional limitation

SourceRenaud, [1992] 2 SCR 970; Meiorin, [1999] 3 SCR 3.

Disclosure

Informing an institution of a disability in order to obtain access. Most accommodation systems require it.

Disclosure carries costs that the requesting system does not measure: stigma, loss of privacy, and repeated explanation. Erving Goffman's account of stigma management describes the reasoning behind non-disclosure. Design that reduces the frequency with which disclosure is necessary reduces those costs.

See alsoAccommodationUniversal Design for LearningFunctional limitation

SourceGoffman (1963); Dolmage (2017).

14 terms

Conformance, standards and evaluation

The technical vocabulary of digital accessibility, including the distinction between meeting a standard and being usable.

Accessibility

The property of a product, environment or service that allows disabled people to use it for its purpose on terms comparable to anyone else.

It describes a relationship between an artefact and the people using it, and cannot be established by inspecting the artefact alone.

See alsoConformanceUsabilityBarrier

SourceCAN/ASC-EN 301 549:2024; W3C, WCAG 2.2 (2023).

Conformance

Meeting the requirements of a technical standard, assessed criterion by criterion against a stated version and level.

Conformance is distinct from accessibility. Content can satisfy every success criterion and still prevent a person from completing the task it exists for. Results are reported as findings requiring interpretation rather than as a pass or a failure.

See alsoAccessibilityUsabilityConformance claimAutomated and manual testing

SourceW3C, WCAG 2.2 (2023); W3C, WCAG-EM 1.0.

Usability

Whether a person can complete a task with reasonable effort, and whether the interface consumes attention that belongs to the task.

The interval between conformance and usability is what evaluation with users is designed to measure.

See alsoConformanceAccessibilityBarrier

SourceW3C, WCAG-EM 1.0; W3C, Selecting Web Accessibility Evaluation Tools.

Barrier

Anything in a product, environment, practice or policy that prevents or impedes participation. The Accessible Canada Act defines the term broadly, covering architectural, technological, attitudinal, informational and policy barriers.

Statistics Canada reported in the 2022 Canadian Survey on Disability that more than seven in ten disabled Canadians aged 15 and over encountered at least one of twenty-seven barrier types.

See alsoSocial modelAccessibilityAdverse effect discrimination

SourceAccessible Canada Act; Statistics Canada, Canadian Survey on Disability (2022).

WCAG

The Web Content Accessibility Guidelines, published by the World Wide Web Consortium. Version 2.2 became a W3C Recommendation in October 2023.

It is organised under four principles: content must be perceivable, operable, understandable and robust. Guidelines sit beneath the principles, and the testable success criteria beneath those.

See alsoSuccess criterionConformance levels A, AA and AAACAN/ASC-EN 301 549:2024Conformance

SourceW3C, WCAG 2.2 (2023).

Success criterion

A single testable requirement in WCAG, written so that it can be evaluated as met or not met without reference to a particular technology.

Success criteria are the unit against which conformance is assessed. They state requirements rather than the effects a person encounters, so findings are commonly reported in both forms.

See alsoWCAGConformance levels A, AA and AAAConformance claim

SourceW3C, WCAG 2.2 (2023); W3C, WCAG-EM 1.0.

Conformance levels A, AA and AAA

Three cumulative tiers in WCAG. Level A covers the most basic requirements. Level AA adds the criteria adopted as the operative standard by most legislation and policy. Level AAA includes criteria that cannot be satisfied for all content of all types.

The W3C does not recommend Level AAA as a general policy target for entire sites. Individual AAA criteria may be applied where they are achievable.

See alsoWCAGSuccess criterionConformance

SourceW3C, WCAG 2.2 (2023).

CAN/ASC-EN 301 549:2024

Canada's national standard for accessibility requirements in information and communication technology. Accessibility Standards Canada adopted it in May 2024 as an identical adoption of the European standard EN 301 549:2021, and publishes it free of charge.

It incorporates WCAG and extends beyond web content to hardware, software, documents and support services. It is the technical benchmark referenced by the federal Digital Technologies Accessibility Regulations.

See alsoWCAGConformanceAccessibility statementAccessibility conformance report

SourceCAN/ASC-EN 301 549:2024; Accessible Canada Act.

Conformance claim

A formal statement that content meets a named standard at a named level, recording what was tested, when, against which version, and what was found.

A claim cannot be made where it is not feasible to monitor or correct non-conforming content. Guidance on accessibility statements notes that overstating conformance creates liability and reduces credibility if the gap is subsequently identified.

See alsoStatement of partial conformanceAccessibility statementAccessibility conformance reportConformance

SourceW3C, WCAG 2.2 (2023); W3C, WCAG-EM 1.0.

Statement of partial conformance

A declaration that content does not conform, but would conform if specified parts drawn from sources outside the publisher's control were removed. The statement identifies those parts and describes how the uncontrolled content relates to overall conformance.

The mechanism addresses third-party content and content generated by users.

See alsoConformance claimAccessibility statementConformance

SourceW3C, WCAG 2.2 (2023).

Accessibility conformance report

A document summarising the extent to which an ICT product or service conforms to a set of accessibility standards, criterion by criterion. The Voluntary Product Accessibility Template is the most widely used format.

Each criterion is recorded as supports, partially supports, does not support, or not applicable. Reports are used principally in procurement and tendering.

See alsoConformance claimCAN/ASC-EN 301 549:2024

SourceIAAP, WAS Body of Knowledge; CAN/ASC-EN 301 549:2024.

Accessibility statement

A public page describing how accessible a site or service is: the standard it aims at, how it was tested, the assistive technology it was tested with, known limitations, and how to report a barrier.

Guidance recommends describing limitations in ordinary terms rather than by criterion number. Under the federal Digital Technologies Accessibility Regulations, accessibility statements become mandatory for federally regulated entities on a schedule beginning in December 2027.

See alsoConformance claimStatement of partial conformanceCAN/ASC-EN 301 549:2024

SourceCAN/ASC-EN 301 549:2024; Accessible Canada Act; W3C, WCAG-EM 1.0.

WCAG-EM

The Website Accessibility Conformance Evaluation Methodology, a W3C Working Group Note setting out a procedure for evaluating a complete website: define the scope, explore the site, select a representative sample, audit the sample, and report.

Its principal contribution is the sampling procedure. A sample selected without method produces findings that cannot be generalised across the site.

See alsoConformanceConformance claimSuccess criterion

SourceW3C, WCAG-EM 1.0.

Automated and manual testing

Automated tools detect a subset of accessibility problems reliably: missing alternative text, insufficient contrast, absent form labels, and invalid markup patterns.

Manual testing covers what automation does not: keyboard-only navigation, screen reader behaviour, magnification and reflow, and whether alternative text conveys the function of an image. The W3C states that evaluation tools cannot determine accessibility on their own and can only assist in doing so.

See alsoConformanceUsabilityWCAG-EM

SourceW3C, Selecting Web Accessibility Evaluation Tools; W3C, WCAG-EM 1.0.

13 terms

Assistive technology

Technologies used to access digital content and physical environments, and the associated terms of art.

Assistive technology

Any item, equipment or system used to increase, maintain or improve the functional capability of a disabled person. The category ranges from screen readers to wheelchairs to medication organisers.

Digital content is frequently rendered through such technology rather than consumed as authored, and the quality of that rendering depends on the underlying structure.

See alsoAccess technologyBuilt-in accessibility featuresScreen readerHAAT model

SourceCook & Polgar (2015); IAAP, CPACC Body of Knowledge (2023).

Access technology

A narrower term for technology whose purpose is to provide access to digital information and communication, as distinct from assistive technology in general.

The two terms are often used interchangeably. Where a distinction is drawn, access technology refers to the software layer mediating digital content, and assistive technology to the broader category including mobility and daily living equipment.

See alsoAssistive technologyScreen readerBuilt-in accessibility features

SourceIAAP, CPACC Body of Knowledge (2023); Cook & Polgar (2015).

Built-in accessibility features

Accessibility functions included in mainstream operating systems, browsers and applications: magnification, contrast and colour adjustment, captions, dictation, and the screen readers shipped with every major platform.

A substantial proportion of access runs through mainstream software rather than specialist equipment. Designing for it consists largely of not interfering with features already present on the user's device.

See alsoAssistive technologyScreen readerSpeech recognition

SourceIAAP, CPACC Body of Knowledge (2023); CAN/ASC-EN 301 549:2024.

Screen reader

Software that conveys on-screen content as synthesised speech or as output to a refreshable braille display, and that provides its own navigation by heading, landmark, link and table cell. Common examples are JAWS and NVDA on Windows, VoiceOver on Apple platforms, and TalkBack on Android.

Headings and landmarks function as navigation rather than as visual styling. Output is generated from the markup rather than from the rendered result, so two pages that appear identical can behave differently.

See alsoRefreshable braille displayAlternative textAccessibility supportedAssistive technology

SourceIAAP, WAS Body of Knowledge; IAAP, CPACC Body of Knowledge (2023).

Screen magnifier

Software that enlarges a region of the display, frequently with colour and contrast adjustment and sometimes with speech output.

Magnification reduces the visible field, so a person may be reading a small region of a large layout. Content that depends on noticing an element distant from the point of focus, such as an error message at the top of a long form, is affected.

See alsoScreen readerBuilt-in accessibility features

SourceIAAP, CPACC Body of Knowledge (2023); W3C, WCAG 2.2 (2023).

Speech recognition

Software that converts speech to text and executes spoken commands, used for dictation and for operating an interface without a keyboard or pointer.

Commands generally reference the visible name of a control, so a control's accessible name needs to match its visible label. A button labelled Send but programmatically named Submit may be unreachable by voice.

See alsoAccessibility supportedAlternative textSwitch access

SourceW3C, WCAG 2.2 (2023); IAAP, CPACC Body of Knowledge (2023).

Switch access

Operating a device through one or more switches activated by a movement that is reliable for the user. The interface scans through available options and the switch selects.

Each selection takes time, so interfaces with many controls, deep menus or short time limits impose a significant cost. Keyboard accessibility is generally the substrate on which switch access operates.

See alsoAssistive technologyScreen readerHAAT model

SourceCook & Polgar (2015); IAAP, CPACC Body of Knowledge (2023).

Refreshable braille display

A device with a row of cells whose pins rise and fall to render text as braille, driven by a screen reader.

Output is silent, private, and typically a line at a time. It is the access route for deafblind users, for whom audio output is not an alternative.

See alsoScreen readerAssistive technology

SourceCook & Polgar (2015); IAAP, WAS Body of Knowledge.

Alternative text

A text equivalent for an image, conveying the function the image performs in its context.

The same photograph requires different alternative text in a news article and in a diagnostic exercise. An image whose meaning is carried by adjacent text takes an empty alternative rather than a duplicate one.

See alsoScreen readerSuccess criterionAccessibility supported

SourceW3C, WCAG 2.2 (2023); IAAP, WAS Body of Knowledge.

Accessibility supported

A term of art in WCAG. A technology or technique is accessibility supported when it works with the assistive technologies and platform features that users have available, rather than when a specification indicates that it should.

A technique that fails in the screen readers in current use is not accessibility supported, irrespective of what the specification permits.

See alsoWCAGConformanceScreen readerSpeech recognition

SourceW3C, WCAG 2.2 (2023).

HAAT model

The Human, Activity, Assistive Technology model developed by Albert Cook and Jan Polgar. It frames an assistive technology decision as a relationship between the person, the activity, the technology, and the context in which all three sit.

The model is applied diagnostically: a technology that ceases to work may be responding to a change in the activity or the context rather than to a limitation of the device.

See alsoSETT frameworkAssistive technologyAbandonment

SourceCook & Polgar (2015).

SETT framework

Student, Environments, Tasks, Tools. Joy Zabala's framework for assistive technology decisions in education, in which the tool is selected last, after the other three have been described.

It establishes a sequence for decision-making, and is applied as a corrective to selection that begins from a product.

See alsoHAAT modelAssistive technologyAbandonment

SourceZabala (2005).

Abandonment

Assistive technology that is acquired and subsequently not used. Reported rates vary considerably across studies according to device type, population, and the definition applied.

The literature associates abandonment with the user's involvement in selection, changes in need, and device performance in context. Both HAAT and SETT address this through the sequence in which decisions are made.

See alsoHAAT modelSETT frameworkAssistive technology

SourceCook & Polgar (2015); Zabala (2005).

7 terms

Learning design and assessment

Terms from learning design and educational measurement that carry distinct meanings.

Universal Design for Learning

A framework from CAST for designing learning environments that anticipate variability from the outset, organised around multiple means of engagement, representation, and action and expression. Version 3.0 of the Guidelines was released in July 2024.

UDL reduces the frequency with which individual accommodation is required. It does not displace the duty to accommodate. The two address different questions: one a design posture toward a population, the other a legal obligation to an individual.

See alsoUniversal DesignAccommodationLearner variabilityDifferentiation

SourceCAST, UDL Guidelines 3.0 (2024); Meyer, Rose & Gordon (2014).

Universal Design

The design of products and environments to be usable by as many people as possible without adaptation or specialised design. Ronald Mace introduced the term, and the seven principles were articulated in 1997 by a group at North Carolina State University: equitable use, flexibility in use, simple and intuitive use, perceptible information, tolerance for error, low physical effort, and size and space for approach and use.

The concept originates in architecture and industrial design. Universal Design for Learning applies it to learning environments.

See alsoUniversal Design for LearningAccessibilityAccommodation

SourceConnell et al. (1997).

Learner variability

The observation that learners differ across multiple dimensions simultaneously, that those dimensions are weakly correlated, and that an average across them describes few individuals.

Variability and disability are distinct concepts carrying distinct legal and ethical claims. Design that addresses variability does not remove the requirement for individual accommodation.

See alsoUniversal Design for LearningDifferentiationAccommodation

SourceRose (2016); CAST, UDL Guidelines 3.0 (2024).

Differentiation

Adjusting content, process, product or learning environment in response to learners already known to the teacher, associated principally with Carol Ann Tomlinson.

Differentiation is retrospective and individual. Universal Design for Learning is prospective and structural, building options into the design in advance. The two are compatible and are not equivalent.

See alsoUniversal Design for LearningLearner variabilityAccommodation

SourceTomlinson (2014); Meyer, Rose & Gordon (2014).

Construct

The capability an assessment is intended to measure, as distinct from the task used to elicit it or the score it produces.

Identifying the construct is the precondition for determining which adjustments preserve the measurement and which alter it.

See alsoConstruct validityConstruct-irrelevant varianceEssential requirement

SourceMessick (1989); AERA, APA & NCME (2014).

Construct validity

The degree to which evidence and theory support the interpretations placed on assessment scores for a proposed use. In Samuel Messick's account, validity is a property of an interpretation rather than of a test.

On that account, a score carries a different meaning if part of what it measured was the candidate's ability to work around the interface.

See alsoConstructConstruct-irrelevant varianceEssential requirement

SourceMessick (1989); AERA, APA & NCME (2014).

Construct-irrelevant variance

Variance in scores produced by factors other than the construct being measured. Thomas Haladyna and Steven Downing's treatment of the concept in high-stakes testing is the standard reference.

Where an inaccessible interface, a required reading speed or an unlabelled diagram contributes to a score, the assessment measures something it did not intend to measure, and the inference drawn from the score is correspondingly weaker.

See alsoConstructConstruct validityAdverse effect discriminationEssential requirement

SourceHaladyna & Downing (2004); Messick (1989); AERA, APA & NCME (2014).

35 sources

Sources

Each entry above cites at least one of the following. Legislation and standards are revised, and case law is distinguished and applied. Anyone acting on a legal or regulatory question should confirm the current position with the issuing body or with counsel.

Legislation

Legislation

Accessible Canada Act, SC 2019, c 10.

Legislation

Human Rights Code, RSBC 1996, c 210.

Case law

Case law

British Columbia (Public Service Employee Relations Commission) v BCGSEU, [1999] 3 SCR 3, 1999 SCC 48 (“Meiorin”).

Case law

British Columbia (Superintendent of Motor Vehicles) v British Columbia (Council of Human Rights), [1999] 3 SCR 868 (“Grismer”).

Case law

Central Alberta Dairy Pool v Alberta (Human Rights Commission), [1990] 2 SCR 489.

Case law

Central Okanagan School District No. 23 v Renaud, [1992] 2 SCR 970.

Case law

Moore v British Columbia (Education), 2012 SCC 61, [2012] 3 SCR 360.

Standard

Standard

Accessibility Standards Canada (2024). CAN/ASC-EN 301 549:2024, Accessibility requirements for ICT products and services (EN 301 549:2021, IDT). National Standard of Canada, available free of charge.

Standard

American Educational Research Association, American Psychological Association, & National Council on Measurement in Education (2014). Standards for Educational and Psychological Testing. AERA.

Standard

W3C (2023). Web Content Accessibility Guidelines (WCAG) 2.2. W3C Recommendation, 5 October 2023.

Standard

World Health Organization (2001). International Classification of Functioning, Disability and Health (ICF). WHO.

Guidance

Guidance

W3C Web Accessibility Initiative. Selecting Web Accessibility Evaluation Tools.

Guidance

W3C Web Accessibility Initiative. Website Accessibility Conformance Evaluation Methodology (WCAG-EM) 1.0. W3C Working Group Note.

Instrument

Instrument

United Nations (2006). Convention on the Rights of Persons with Disabilities. UN General Assembly, A/RES/61/106.

Body of knowledge

Body of knowledge

International Association of Accessibility Professionals (2023). Certified Professional in Accessibility Core Competencies (CPACC) Body of Knowledge. IAAP, a division of G3ict.

Body of knowledge

International Association of Accessibility Professionals. Web Accessibility Specialist (WAS) Body of Knowledge. IAAP.

Framework

Framework

CAST (2024). Universal Design for Learning Guidelines, version 3.0.

Framework

Connell, B. R., Jones, M., Mace, R., Mueller, J., Mullick, A., Ostroff, E., Sanford, J., Steinfeld, E., Story, M., & Vanderheiden, G. (1997). The Principles of Universal Design, Version 2.0. Center for Universal Design, North Carolina State University.

Framework

Zabala, J. (2005). Ready, SETT, Go! Getting Started with the SETT Framework. Closing the Gap.

Book

Book

Charlton, J. I. (1998). Nothing About Us Without Us: Disability Oppression and Empowerment. University of California Press.

Book

Cook, A. M., & Polgar, J. M. (2015). Assistive Technologies: Principles and Practice (4th ed.). Elsevier.

Book

Dolmage, J. T. (2017). Academic Ableism: Disability and Higher Education. University of Michigan Press.

Book

Goffman, E. (1963). Stigma: Notes on the Management of Spoiled Identity. Prentice-Hall.

Book

Kafer, A. (2013). Feminist, Queer, Crip. Indiana University Press.

Book

Meyer, A., Rose, D. H., & Gordon, D. (2014). Universal Design for Learning: Theory and Practice. CAST Professional Publishing.

Book

Oliver, M. (1990). The Politics of Disablement. Macmillan.

Book

Rose, T. (2016). The End of Average: How We Succeed in a World That Values Sameness. HarperOne.

Book

Shakespeare, T. (2013). Disability Rights and Wrongs Revisited (2nd ed.). Routledge.

Book

Titchkosky, T. (2011). The Question of Access: Disability, Space, Meaning. University of Toronto Press.

Book

Tomlinson, C. A. (2014). The Differentiated Classroom: Responding to the Needs of All Learners (2nd ed.). ASCD.

Chapter

Chapter

Messick, S. (1989). “Validity.” In R. L. Linn (Ed.), Educational Measurement (3rd ed., pp. 13–103). Macmillan.

Article

Article

Haladyna, T. M., & Downing, S. M. (2004). “Construct-Irrelevant Variance in High-Stakes Testing.” Educational Measurement: Issues and Practice, 23(1), 17–27.

Article

Retief, M., & Letšosa, R. (2018). “Models of Disability: A Brief Overview.” HTS Teologiese Studies / Theological Studies, 74(1).

Text

Text

Sins Invalid (2019). Skin, Tooth, and Bone: The Basis of Movement is Our People (2nd ed.). Sins Invalid.

Data

Data

Statistics Canada (2023). Canadian Survey on Disability, 2022.