A Web Accessibility Primer: Part 1

With the Accessibility for Ontarians with Disabilities Act (AODA) coming into full effect by 2025, we get a lot of questions from clients about its impact on web design and the consequences of not being compliant.

A big part of understanding a new subject is learning to speak the language, so we’ve put together a guide of common terms to help you understand accessibility and AODA compliance from the vantage point of designing, coding, and producing content for your next digital project.

The basics

1. Disability

From a medical perspective disability is a physical, sensory, or cognitive impairment in ability. From a social perspective disability refers to a physical or intangible barrier that limits an individual’s access to spaces, opportunities, or other environments (e.g. digital environments).

2. Web Accessibility

The measure of web page or application usability by persons with one or more disabilities.

3. Assistive Technologies (ATs)

Technologies (software or hardware) that increase, maintain, or improve the interaction between a computer/system and the end user.

Design approaches

4. Accessible Design

Design of systems and products that meet prescribed code requirements of the latest laws and legislations, such as the AODA.

5. Adaptable Design

A subset of Accessible Design, this is the very specific adaptation of products and systems in order to make them usable on an individual, as-needed basis.

6. Inclusive Design

An Accessible Design approach that considers user diversity and advocates for usability by as many people as reasonably possible, without the need for individual adaptation. Inclusive designers do not suggest that it is always possible or appropriate to design one product to address the needs of the entire population.

7. Universal Design

An approach to Accessible Design of products and systems that considers how they can be used and experienced by people of all ages, disabled and non-disabled, to the greatest extent possible, without the need for individual adaptation.

Regulations and legislation


The Accessibility for Ontarians with Disabilities Act will be in full effect on or before January 1, 2025. “The purpose of the act is to benefit all Ontarians by developing, implementing and enforcing accessibility standards with respect to goods, services, facilities, accommodation, employment, buildings, structures, and premises” (AODA, 2015). To meet AODA on the web, your website or product must conform to WCAG 2.0 guidelines.

9. WCAG 2.0

The Web Content Accessibility Guidelines 2.0; currently, those guidelines have been adopted by the AODA in Ontario and Section 508 of the Rehabilitation Act in the United States.

10. WCAG 2.0 Guidelines

There are 12 guidelines that each fall under one of the 4 principles of web accessibility (defined below). These guidelines provide goals and tenets that web designers and authors should strive toward in order to make content and websites accessible to users and compatible with different browser and ATs.

11. WCAG 2.0 Success Criteria

Testable design or code specifications that accompany each WCAG guideline. These criteria are further subdivided into levels of conformance. Some websites might meet all Level A Criteria, but might only meet some or none of the AA or AAA Criteria.

12. Conformance

Conformance refers to how well your product adheres to or complies with the set of requirements outlined in the guidelines and success criteria of WCAG 2.0. Discrete levels of conformance have been designated, from lowest (A) to highest (AAA).

13. WCAG 2.0 Level A, AA, AAA

The three different levels of Success Criteria conformance (from lowest to highest), as outlined by WCAG 2.0. By January 1, 2020, all websites must conform fully to level AA.

Let’s take guideline 1.4.3 Contrast (minimum):
The guideline states that the presentation of text and images as text needs to have a contrast ratio of at least 4.5:1 in order to meet level AA.

The success criterion for this guideline is to meet or surpass this minimum contrast ratio when the text colour and background colour are analyzed with a contrast checker (e.g. WebAIM).


Example of AA compliant color contrast

It is encouraged for websites and systems to strive for AAA where possible, but this is not (yet) a legal mandate.

Continuing with the colour contrast example, conforming to guideline 1.4.6 Contrast (Enhanced) means the website text and background colours have a contrast ratio of at least 7:1, meeting level AAA success criterion.

Example of AAA compliant color contrast

14. Four principles of web accessibility

Developed by WCAG, these design “principles provide the foundation for web and digital accessibility” (WCAG 2.0, 2015). Corresponding to Guidelines and Success Criteria, the principles provide actionable techniques to help us design solutions that conform to WCAG 2.0.

a) Perceivable
Web-based content and interface components must be presented in ways that all users can perceive, regardless of individual impairment.

Example: in conformance with WCAG 2.0 guideline 1.1, a website must provide text alternatives for all image based content.

b) Operable
All users accessing a website or application, regardless of their preferred usage method (mouse, keyboard, voice recognition, switches or input device) must be able to simply and accurately manipulate the interface and navigation components.

Example: in conformance with WCAG 2.0 guideline 2.1 all website functionality must be available via the keyboard.

c) Understandable
Content and interfaces are as clear as possible so that all people understand the website.

Example: in conformance with WCAG 2.0 guideline 3.3, the website must be equipped to help users avoid and correct mistakes (e.g. form input, navigation).

d) Robust
Ensure web content can be interpreted reliably by the widest variety of browsers, devices, and assistive technologies.

Example: in conformance with WCAG 2.0 guideline 4.1, the website must be compatible with current and future browsers, applications, and ATs, to the fullest extent possible.

Stay tuned for our next post, where we will look these four principles in more detail! In the meantime, feel free to check out this post that includes a downloadable infographic on Why Accessibility is Important.





[PRINT] RGD Access Ability – A practical handbook on accessible graphic design


Story, M.F. (1998). Maximizing Usability: The Principles of Universal Design. Assistive Technology, 10:1, 4-12.