15 Design Principles/Heuristics

Discoverability

Is it possible to even figure out what actions are possible and where and how to perform them?

Simplicity

The user should only be given as much information as they need.
Can people of different experiences, levels of knowledge, or languages can figure out what to do? The design should make simple common tasks easy.

Affordances

An affordance is the relationship between the properties of an object and the capabilities of the agent that determine just how the object could possibly be used. You can look at it and know how to use it. I.e. a button or handle. This one is confusing because of the difference in a percieved affordance and an actual affordance. Signifiers are used to make the perceived and the actual match up. I.e. putting a “push” label on a door.

Mapping

The system should speak the users' language, with words, phrases, and concepts that are familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

Perceptability

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

Consistency

Lessons learned with one system transfer readily to others. If a new way of doing things is only slightly better than the old, it's better to be consistent.

Flexibility

Designs should accommodate a wide range of individual preferences and user abilities. A good example is CTRL+C versus right click, copy.

Equity

Designs should provide the same means of use for all users: identical whenever possible, equivalent when not. Designs should avoid segregating or stigmatizing any users. Ultimately, all users should have the same experience.

Ease and Comfort

The design can be used efficiently and comfortably and with a minimum amount of fatigue.

Structure

Putting related things together and separating unrelated things helps the user's mental model match the actual content of the task.

Constraints

A careful design which prevents a problem from occurring in the first place.

Tolerance

Users shouldn't be at risk of causing too much trouble accidentally and need a clearly marked 'emergency exit' to leave the unwanted state.

Feedback

Feedback must be immediate and it must be informative.

Documentation

Should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.