The POUR acronym—perceivable, operable, understandable, robust—is a concept used in accessibility to represent the four key principles used to make something accessible on the web.
Here’s a breakdown of these four principles:
Perceivable
Users can use a range of senses to easily identify content and user interface functionality.
Example: Colour contrast is sufficient for users to easily read text that sits on a background.
Operable
This principle focuses on the functionality of the interface through a range of means; from mouse, to keyboard, to voice.
Example: Keyboard navigation and the tab key allow the user to jump from link to link on the site without getting stuck or confused.
Understandable
This principle focuses on whether the content and features are simple and consistent. This principle’s success factors include a level of content that can be understood by all, and an intuitive, easy-to-use interface.
Example: Content is at a reading level that is not too difficult for the audience to understand (10th grade or below).
Robust
The robust principle is focused on determining if an interface or website meets reasonable technology standards, including functioning across different devices and browsers.
Example:Does the site work in Safari, Chrome, and Firefox?