HCI Design Issues

1
HCI Design Issues

• As long as it looks pretty,
• thats fine, isnt it?

2
Usability

• User experience goals
• Satisfying
• Enjoyable
• Fun
• Entertaining
• Helpful
• Motivating
• Aesthetically pleasing
• Supportive of creativity
• Rewarding
• Emotionally fulfilling

• Usability Goals
• Effective to use
• Efficient to use
• Safe to use
• Have good utility
• Easy to learn
• Easy to remember how to use

3
Design Usability Principles(Don Norman, 1988,
The Design of Everyday Things)

• Visibility
• Maximise think about a cars controls
• Feedback - related to visibility!
• Tell user what has been done visual, audio,
  tactile, verbal etc
• Constraints
• deliberate design to restrict user interaction
• 3 categories physical, logical, cultural
• Mapping
• relationship between controls their effects
• Consistency
• Similar ops, similar elements eases learning!
• Affordance
• Perceived object attribute that allows user to
  know how to use it

4
Shneidermans 8 Golden Rules for Dialogue Design

• Strive for consistency
• Enable frequent users to use shortcuts
• Offer informative feedback
• Design dialogue to yield closure

• Offer simple error handling
• Permit easy reversal of actions
• Support internal locus of control
• Reduce short-term memory load

5
Interaction Design

• Investigation of artifacts use and target domain
  from users viewpoint
• Hence users concerns direct development rather
  than technical
• Trading off conflicting requirements to find best
  fit
• 4 basic activities
• Identify needs establish requirements
• Develop alternative designs
• Build interactive versions of designs
• Evaluate the designs

6
ID Practical Issues

• Must be able to answer these questions beforehand
• Who are the users?
• What do we mean by needs?
• How do you generate alternative designs?
• How do you choose between alternatives?

7
Things for designers to consider!

• The user is human! Humans incredibly diverse
• ability background
• cognitive style
• personality
• Humans undertake tasks
• understand the humans real task
• understand how why achieved
• comprehend effect computerisation might have
• Errors - system or user?

8
Lifecycle Models

• Lots of different ones!
• From S/W Engineering
• Waterfall (1970)
• Spiral (Barry Boehm 1988)
• RAD (Early 1990s) (some focus on user!)
• From HCI
• Star (Hartson Hicks 1989)
• Usability Engineering (Deborah Mayhew, 1999)

9
Simple ID Lifecycle Model (Preece,Rogers
Sharp, 2002, Interaction Design, Wiley, p186)
Identify needs/ establish requirements
Evaluate
(Re)Design
Final product
Build an interactive version