Heuristics
These usability principles should befollowed by all user interface designers.
This specific list was developed by Jacob Nielsen and Rolf Molich
(Molich, Nielsen 90).
-
Simple and natural dialogue: Dialogues should not contain
information that is irrelevant or rarely needed. Every extra
unit of information in a dialogue competes with the relevant
units of information and diminishes their relative visibility.
All information should appear in a natural and logical order.
- Speak the users' language: The dialogue should be expressed
clearly in words, phrases, and concepts familiar to the user,
rather than in system-oriented terms.
- Minimize the users' memory load: The user should not have to
remember information from one part of the dialogue to another.
Instructions for use of the system should be visible or easily
retrievable whenever appropriate.
- Consistency: Users should not have to wonder whether different
words, situations, or actions mean the same thing.
- Feedback: The system should always keep users informed about
what is going on, through appropriate feedback within reasonable
time.
- Clearly marked exits: Users often choose system functions by
mistake and will need a clearly marked "emergency exit" to leave
the unwanted state without having to go through an extended
dialogue.
- Shortcuts: Accelerators - unseen by the novice user - may often speed
up the interaction for the expert user such that the system can
cater to both inexperienced and experienced users.
- Good error messages: They should be expressed in plain language
(no codes), precisely indicate the problem, and constructively
suggest a solution.
- Prevent errors: Even better than good error messages is a
careful design that prevents a problem from occurring in the
first place.
-
Help and documentation: Even though it is better if the system
can be used without documentation, it may be necessary to
provide help and documentation. Any such information should be
easy to search, be focused on the user's task, list concrete
steps to be carried out, and not be too large.
more information
Exercise
Example