Design principles can guide the designer during the design process and can be used to  

evaluate and critique prototype design ideas. 

▪ Principles 1-4 are concerned with access, ease of learning and remembering (learnability) 

▪ Principles 5-7 are concerned with ease of use, and principles 8 and 9 with safety  

(effectiveness). 

▪ Principles 10-12 are concerned with accommodating differences between people and  

respecting those differences (accommodation). 

Principles 1: Visibility 

Try to ensure that things are visible so that people can see what functions are available and what the system is currently doing. Consider making things Visible’ through the use of sound and touch. 

Principles 2: Consistency 

Be consistent in the use of design features and be consistent with similar systems and standard ways of working. Both conceptual and physical consistency are important. 

Principles 3: Familiarity 

Use language and symbols that the intended audience will be familiar with. 

Principles 4: Affordance 

Affordance refers to the properties that things have (or are perceived to have) and how these relate to how the things could be used. Buttons afford pressing, chairs afford sitting on, and Post-it notes afford writing a message on and sticking next to something else. Affordances are culturally determined. 

Principles 5: Navigation 

Provide support to enable people to move around the parts of the system: maps, directional signs and information signs. 

Principles 6: Control 

Make it clear who or what is in control and allow people to take control. Control is enhanced if there is a clear, logical mapping between controls and the effect that they have. Also make clear the relationship between what the system does and what will happen in the world outside the system. 

Principles 7: Feedback 

Rapidly feedback information from the system to people so that they know what effect their 

actions have had. Constant and consistent feedback will enhance the feeling of control. 

Principles 8: Recovery 

Enable recovery from actions, particularly mistakes and errors, quickly and effectively. 

Principles 9: Constraints 

Provide constraints so that people do not try to do things that are inappropriate. In particular, people should be prevented from making serious errors through properly constraining allowable actions and seeking confirmation of dangerous operations.  

Principles 10: Flexibility 

Allow multiple ways of doing things so as to accommodate people with different levels of experience and interest in the system. Provide people with the opportunity to change the way things look or behave so that they can personalize the system. 

Principles 11: Style. 

Designs should be stylish and attractive 

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