The four principles of accessibility
To help simplify the complex subject of accessibility, we’ve put together a quick guide to accessibility’s P.O.U.R. principles.
Accessibility
Accessibility is a broad topic that encompasses a range of aspects, from abstract legal rulings to specific coding guidelines. The industry standard guidelines for web content accessibility are organized around four principles: Perceivable, Operable, Understandable and Robust (or POUR). To help you understand the basics of accessibility, we’ve put together an introduction to these principles.
Perceivable
Starting at the most basic level, users must be able to process information. Information that is not presented in a processable format is not accessible. Among other affordances, this means providing text for those who are visually impaired and audio for those who are blind or have low vision. It does not mean creating audio for every text, but the content must be consumable by screen readers and other assistive technologies. Websites and apps that require sight or hearing won’t pass the test of perceivability.
Ask yourself: Is there anything on our website that a blind, deaf, low-vision or color-blind user would not be able to perceive?
Operable
People with disabilities need to be able to access and operate websites and applications with a variety of tools. Many users with disabilities are unable to operate a mouse. Alternatives such as keyboard-based operation should be implemented.
To help users with cognitive disabilities operate a website, animations and media should be controllable, and time limits for completing an action should be generous or configurable. Most importantly, sites and apps should be forgiving. All people, not just those with disabilities, make mistakes. Offer second chances, instructions, cancellation options and warnings to help all users.
Ask yourself: Can all functions of our website be performed with a keyboard? Can users control the interactive elements of our website? Does our website make completing tasks easy?
Understandable
If users can perceive and operate a website, that doesn’t mean they can understand it. Understandable websites use clear, concise language and offer functionality that is easy to comprehend. If a user takes an action, the connection between the action and the result should be obvious. Navigation should be used consistently across a site. Forms should follow a logical flow and provide clear labels. If a user must go through a process, like a checkout, adequate guidance should be provided. If this feels like usability and not accessibility, that’s because usable websites are inherently more accessible.
Ask yourself: Is all of the text on our website clearly written? Are all of the interactions easy to understand?
Robust
Users pick their own mix of technologies. Within limits, websites should work well enough across platforms, browsers and devices to account for personal choice and user need. While users cannot expect a website to support Internet Explorer 1.0, sites should not dictate the technology users can use. When sites dictate supported technology platforms, they restrict access for any non-conforming user. One of the best ways to meet the principle of robustness is to follow development standards and conventions. Clean code is generally more robust and easier to consume across platforms.
Ask yourself: Does our website only support the newest browsers or operating systems? Is our website developed with best practices?
Conclusion: An accessible experience is a better experience for all
The P.O.U.R. principles — Perceivable, Operable, Understandable, and Robust — offer more than just a framework for compliance. They provide a clear path to creating more intuitive, forgiving and user-friendly digital products for everyone. As you've likely noticed, these principles overlap heavily with the fundamentals of good design and usability.
By asking the simple questions posed by P.O.U.R., you shift the focus from simply meeting standards to serving people. The result is an experience that not only opens your services to a wider audience but also builds brand trust and improves satisfaction for your entire customer base.
While these principles provide a strong foundation, implementing them effectively requires a deep commitment across strategy, design and development. At TELUS Digital, our teams embed accessibility into every stage of the product lifecycle, from initial strategy to post-launch support. If you're ready to create digital experiences that are truly open to all, let's connect.
