The Four Principles: Perceivable, Operable, Understandable, Robust
All of WCAG is organised around four simple principles, often shortened to POUR. Every detailed rule sits under one of them, so understanding the four gives you a clear mental map of what accessibility is really about.
You do not need to memorise hundreds of criteria. If your site honours these four ideas, the specific rules tend to fall into place.
Perceivable
Information must be presentable in ways people can sense, whatever their abilities. Images need text alternatives, video needs captions, and content must not rely on colour alone.
Operable
People must be able to operate the interface — with a keyboard, with a mouse, or with assistive technology. Nothing should require an interaction a person cannot perform.
Understandable and Robust
Content and controls must be clear and predictable, and the underlying code must be solid enough to work reliably with browsers and assistive tools, now and in the future.
- Understandable: readable text, predictable navigation, helpful error messages.
- Robust: clean, standards-based code that assistive technology can interpret.
If you need a hand with any of this, your Progressive Robot delivery team is ready to help. Raise a ticket from the Support area of your client portal or speak to your account manager and we will guide you through the next steps.