Trust Test Transparency Test Social Responsibility & Accountability Test Ease of use Higher Quality Better Pricing No Effortg To sell/Buy Uniqueness

Visibility of system statusThe system should always keep users informed about what is going on, through appropriate feedback within reasonable time. Match between system and the real worldThe system should speak the users' language, with words, phrases and concepts familiar to the user User control and freedom 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. Support undo and redo. Consistency and standardsUsers should not have to wonder whether different words, situations, or actions mean the same thing Error prevention Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Recognition rather than recall Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Flexibility and efficiency of use 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. Allow users to tailor frequent actions. Aesthetic and minimalist design use Dialogues should not contain information which is irrelevant or rarely needed. Help users recognize, diagnose, and recover from errors Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution. 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, focused on the user's task, list concrete steps to be carried out, and not be too large.