POUR Principles

The four foundational principles of the Web Content Accessibility Guidelines (WCAG): Perceivable, Operable, Understandable, and Robust. Perceivable means information must be presentable in ways users can perceive (e.g., alt text for images, captions for video). Operable means interface components must be navigable and interactive for all users (e.g., keyboard accessibility). Understandable means content and interface operation must be comprehensible (e.g., clear labels, predictable navigation). Robust means content must be interpreted reliably by a wide variety of user agents and assistive technologies. Analysis of developer discussions shows Perceivable issues dominate (60% of accessibility questions), followed by Operable (34%), with Understandable (4%) and Robust (2%) receiving far less attention — a potential gap in developer awareness.