Which principle is associated with the guideline "Make web pages appear and operate in predictable ways"?

The principle associated with the guideline "Make web pages appear and operate in predictable ways" is Understandable. This principle emphasizes the importance of ensuring that users can comprehend how to interact with web content without confusion or uncertainty. When a web page operates in a consistent and predictable manner, it enhances the user's ability to understand how to navigate the site, complete tasks, and find the information they need efficiently. This predictability directly contributes to a clearer understanding of the interface and its functionality.

In line with the Understandable principle, designers and developers should use consistent navigation patterns, clear labeling, and familiar layout structures to aid comprehension. By maintaining predictability in user interfaces, accessibility is improved for all users, not just those with disabilities, as it reduces cognitive load and enhances usability.