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Accessibility Matters

by  mangrove team
published on 03.25.2020

With an estimated 48.9 million people in the US living with a disability, it’s crucial for companies to prioritize website accessibility.

First and foremost, it’s important from a values perspective—making the web accessible to the widest range of people is simply the right thing to do. It may also be important from a legal perspective. The Web Accessibility Initiative has established guidelines intended to afford everyone equal access to online content. Companies that fail to comply with their standards risk being sued under the Americans with Disabilities Act. This article presents an overview of what this all means and what you should consider to make your site more accessible to all users.

This is part 1 of a 4-part series on web accessibility. Check out our other articles in the series:

Where do accessibility standards come from?

How can we ensure that the web is accessible to as many people as possible? The Web Accessibility Initiative (WAI) has established a series of testable criteria referred to as Web Content Accessibility Guidelines. The guidelines outline content, design and coding parameters that set the international accessibility standard.

The "POUR" Principles of Accessibility

The four main guiding principles of accessibility in WCAG 2.0 are:
(note: descriptions in this list are taken straight from, and links point to a wealth of additional information on each of the POUR principles via

  • Perceivable – Information and user interface components must be presentable to users in ways they can perceive. This means that users must be able to perceive the information being presented (it can’t be invisible to all of their senses)
  • Operable – User interface components and navigation must be operable.
    This means that users must be able to operate the interface (the interface cannot require interaction that a user cannot perform)
  • Understandable – Information and the operation of user interface must be understandable.
    This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding)
  • Robust – Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
    This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible)

If any of the above principles are not true, users with disabilities may not be able to use your website.

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Understanding the levels of accessibility

The Web Content Accessibility Guidelines fall into three levels of conformance:

  • “A” covers the basics and is the easiest to meet. It makes a website easier to navigate with assistive technology, and takes into account color contrast, text sizing, and other elements that form the foundation of an accessible site.
  • “AA” addresses a wider range of accessibility challenges. This level should be the goal for most sites focused on accessibility compliance to satisfy the rules of an institution or a legal requirement. It is most often the level of accessibility that needs to be met when referenced by the W3C or in legal matters.
  • “AAA” is the highest level of conformance and requires complex updates. Websites rarely reach, nor maintain, this level in all aspects of content, design, and development.

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