Design Rules

Design Rules

1. Golden rules and heuristics

2. (Principles of Usability)

   • 1- Learnability: the ease with which new users can begin effective interaction and achieve maximum performance
     • 1.1 Predictability : it is means that the user’s knowledge of the interaction history is sufficient to determine the result of future interaction.(can I ‘tell’ what will happen based on what I have gone through in past)
     • 1.2 Familiarity : how prior knowledge from real world applies to new system , The appearance of the object stimulates a familiarity with its behavior (like a button on door & form) , Guessability
     • 1.3 Generalizability : Applying specific interaction knowledge to new situations like MS word & excel etc , Can be seen as a form of consistency , applications should offer the Cut/Copy/Paste operations whenever possible
     • 1.4 Consistency : Likeness in input - output behaviour arising from similar operation , The user relies on a consistent interface
   • 2- Flexibility: the variety of ways the user and system exchange information
     • 2.1 Dialogue initiative : Who controls dialouge. freedom from system imposed constraints on input dialogue , a system-driven interaction hinders flexibility whereas a user-driven interaction favours it , user should be able to Cancel, suspend or resume tasks at any point .
     • 2.2 Multithreading : ability of system to support user interaction for more than one task at a time
     • 2.4 Substitutivity : allowing equivalent values of input and output that be substituted for each other , Ex : Margin settings provide measurement in inches & centimetres
     • 2.5 Customizability : Interface can be modified to different needs ex : Colours & layout change, provide choice of methods; allow short-cuts; permit users to change features: deferred design
     • 2.3 Task migratability : Transfer responsibility for task execution between user and system like spell-checking.
   • 3- Robustness: the level of support provided to the user in determining successful achievement and assessment of goal
     • 3.1 Observability : ability of user to evaluate the internal state of the system from its apparent representation
     • 3.2 Recoverability : Support for Undoing errors , ability of user to take corrective action once an error has been recognized , Error messages should be concise, informative, Specific & constructive
     • 3.4 Task conformance/Completeness : degree to which system services support user's tasks , System should perform all the tasks that user needs or wants
     • 3.3 Responsiveness : Measures the rate of communication between the system and user , Response time is generally defined as the duration of time needed by the system to express state changes to the user, short durations and immediate response times are desirable

Bilder und Dateien der Mindmap