<blog>
Understanding WCAG

Image credit: Generated using Microsoft Designer

Originally appeared in LinkedIn AccessABILITY

In my last post I covered “types” of disabilities or impairments in a somewhat detailed manner. In this post I’ll be discussing the Web Content Accessibility Guidelines.

The Web Content Accessibility Guidelines, or WCAG, are a set of recommendations for making web content more accessible to disabled persons. The World Wide Web Consortium (W3C) established these as part of their Web Accessibility Initiative.

A Brief History of WCAG

WCAG 1.0 was officially published in May of 1999, and it established 14 standards across three priority levels for making web content accessible.

• Priority 1 addressed basic criteria such as providing text alternatives for non-text content and ensuring that content made sense when shown in various ways.
• Priority 2 addressed concerns such as captioning audio/video content and allowing style sheets to be bypassed or altered.
• Priority 3 was for enhancing accessibility, such as providing navigation bars, ensuring direct accessibility of embedded user interfaces, and providing metadata about accessibility.

WCAG 1.0 included considerations for web technologies that were likely to evolve over time. While pioneering, WCAG 1.0 had some weaknesses that prompted the development of WCAG 2.0 which was published on December 11, 2008.

WCAG 2.0 took a more technology-neutral approach, emphasizing principles rather than approaches. The requirements were re-organized to reflect overarching design principles to guide the approach in web authoring and content creation. It introduced four broad principles (perceivable, operable, understandable, robust) rather than checklists and included 12 guidelines.

WCAG 2.1 was published on June 5, 2018, and it built upon 2.0 by adding another guideline and 17 success criteria. It was an extension that added criteria for mobile accessibility, people with low vision, and those with cognitive/learning disabilities.

WCAG 2.2 is the latest release, published on October 5, 2023. The new release built upon 2.1 by adding 9 success criteria. It expanded on 2.1 by adding requirements for accessible authentication, content on hover/focus, accessible data tables, and identifying resources to meet user needs.

Guidance from the WCAG

From the W3C, the WCAG describe how to make web content more accessible to individuals with impairments. Web "content" generally refers to the information contained in a web page or web application, including:

• natural information such as text, images, and sounds
• code or markup that defines structure, presentation, etc.

The WCAG are structured around principles, guidelines, testable criteria, and techniques. This allows WCAG to be used for setting requirements, testing conformance, and enabling creative approaches to achieve web accessibility for users with disabilities.

The WCAG documentation also provides advisory techniques, which are tips and best practices to implement the guidelines more effectively beyond just meeting the minimum success criteria. Let’s take a closer look at the building blocks of WCAG.

Principles - At the top are four principles that provide the foundation for Web accessibility: perceivable, operable, understandable, and robust.

Guidelines - Under the principles are guidelines. The 13 guidelines provide the basic goals that authors should work toward to make content more accessible to users with different disabilities. The guidelines are not testable but provide the framework and overall objectives to help authors understand the success criteria and better implement the techniques.

Success Criteria - Each guideline includes testable success criteria, allowing WCAG 2.2 to be used when requirements and conformance testing are required, such as design specifications, purchasing, regulation, and contractual agreements. To fulfill the needs of various groups and situations, three degrees of compliance are defined: A (lowest), AA, and AAA (highest)*.

Sufficient and Advisory Techniques - A wide range of techniques have also been documented by the working group for each of the guidelines and success criteria in the WCAG 2.2 document itself. The methods are instructive and can be divided into two groups: those that are advisory and those that are sufficient to achieve the success requirements. The advice strategies enable authors to handle the guidelines and go above what is required by each unique success criteria more effectively. Testable success criteria do not cover all accessibility barriers; others are addressed by advising strategies.

*Note: Individuals with all sorts, degrees, or combinations of disability will likely be unable to access content that conforms to the highest level (AAA), notably in the cognitive language and learning areas. You should examine the complete range of strategies, including advisory techniques, as well as seek appropriate guidance on current best practices to ensure that Web material is as accessible to this group as possible.

WCAG Principles

Let’s take a quick look at what each of the principles are with a brief description of each. The four foundational principles in WCAG encompass the specific guidelines and success criteria for creating a universally accessible user experience on the web for people with diverse abilities and disabilities. Following the POUR (perceivable, operable, understandable, and robust) principles is key to achieving comprehensive web accessibility.

Perceivable: Can users perceive the content? Information and user interface components must be presented to users in a way they can understand. In other words, it cannot be completely invisible to their senses. Perceivability should take into account the available senses, including sight, hearing, and/or touch.

Operable: Can users use UI components and navigate the content? User interface components and navigation must be operable, or able to be used. This can include things like forms, controls, and navigation. This means that a user must be able to operate interface elements by first identifying them, and then interacting with them either physically or with assistive technology.

Understandable: Can users understand the content? Can users understand the interface and is it consistent enough to avoid confusion? Information and the operation of user interface must be understandable. This means that technology should have predictable usage patterns and design, as well as clear and consistent presentation and format.

Robust: Can the content be consumed by a wide variety of user agents (browsers)? Does it work with assistive technology? Content must be robust enough that it can be interpreted by a wide variety of devices and user agents, including assistive technologies.

Truly understanding and applying these principles requires diving deeper into their nuances and implications. However, we’ve covered a decent amount for you to think about and research in this issue.

Ensuring your web content adheres to WCAG is about more than just checking boxes. It requires fully grasping the POUR conceptual model and how that translates into meeting the technical and user experience requirements spelled out in the guidelines and success criteria. As is the case with most things in life - the devil is in the details.