The Web Content Accessibility Guidelines (WCAG) are a set of international standards intended to inform the accessibility of digital properties (think websites, applications, and digital documents like PDFs). They provide recommendations for improving the usability of web pages for individuals who may have visual, auditory, physical, or cognitive impairments. By following WCAG, organizations can ensure that their online content is easier to navigate, read, and interact with for everyone, including those who rely on assistive technologies like screen readers.
WCAG has evolved through several versions to address new technologies and improve accessibility standards. The first version, WCAG 1.0, was published in 1999 and focused on basic web accessibility techniques. WCAG 2.0, released in 2008, introduced the POUR principles and provided more comprehensive guidelines applicable to a wider range of web content and technologies. WCAG 2.1, published in 2018, expanded on 2.0 by adding criteria for mobile accessibility and cognitive disabilities. Most recently, WCAG 2.2 was released in 2023, further refining requirements to address evolving user needs and digital platforms. Each version builds on the previous one, ensuring ongoing relevance and effectiveness in making digital content accessible for all.
WCAG is organized around four foundational principles known as POUR: Perceivable, Operable, Understandable, and Robust.
- Perceivable: means that users must be able to perceive the information being presented, such as through text alternatives for images.
- Operable: requires that users can interact with interface components, for example, via keyboard navigation.
- Understandable: ensures that content and controls are clear and predictable.
- Robust: means content must be compatible with current and future assistive technologies.
WCAG also defines three levels of conformance: Level A, Level AA, and Level AAA.
- Level A: represents the minimum accessibility requirements,
- Level AA: is the recommended standard for most organizations, and
- Level AAA: is the highest level, offering enhanced accessibility.
Websites and applications are typically expected to meet Level AA to ensure broad usability for people with disabilities.
WCAG has been widely adopted across various sectors. Government agencies in many countries require public websites and online services to comply with WCAG standards. In addition, businesses in the private sector, including financial institutions, e-commerce platforms, and educational organizations, frequently implement WCAG guidelines to mitigate legal risks and serve a diverse audience. Nonprofit organizations also leverage WCAG to make information and resources accessible to individuals with disabilities.
Globally, WCAG has influenced legislation such as the Americans with Disabilities Act (ADA) in the United States and the European Accessibility Act (EAA) in the European Union, making it a cornerstone for web accessibility policies. As a result, the principles and levels of conformance outlined by WCAG are now integral to the design and development of websites and digital applications worldwide.
Manual audits provide a complete view of the failures to the guidelines. Good ones will also provide robust and actionable advice on remediating the failures, in addition to providing metrics to help prioritize the failures and create a successful plan for remediation.
Automated scanning can detect a subset of the issues. Typically, automation will uncover 30 to 40 percent of the failures to the WCAG’s Success Criteria. This can, in many cases, represent up to 70 percent of the failures on a site.