Adapted by Kelly Green <kg@dingonline.com> from Constantine, L.L. (1994). Collaborative Usability Inspections for Software. Software Development '94 Proceedings, San Francisco: Miller Freeman.
Structure Principle--Organize the user interface purposefully, in meaningful and useful ways that put related things together and separate unrelated things based on clear, consistent models that are apparent and recognizable to others.
Simplicity Principle--Make simple, common tasks simple to do, communicat[e] simply in the user's own language and provid[e] good shortcuts that are meaningfully related to longer procedures.
Visibility Principle--Keep all needed options and materials for a given task visible without distracting the user with extraneous or redundant information.
Feedback Principle--Keep users informed of actions or interpretations, changes of state or condition, and errors or exceptions using clear, concise, and unambiguous language familiar to users.
Tolerance Principle--Be flexible and tolerant, reducing the cost of mistakes and misuse by allowing undoing and redoing--canceling and going back--while preventing errors wherever possible by tolerating varied inputs and sequences and by interpreting all reasonable actions reasonably.
Reuse Principle--Reduce the need for users to rethink and remember by reusing internal and external components and behaviors, maintaining consistency with purpose rather than merely arbitrary consistency. Maintain consistency in icons and heading styles to offer visual cues to user's location in the information space.