CIF102FIF102

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CIF102/FIF102

• Session 14
• Design for usability

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What is Human Computer Interaction (HCI)?

• HCI is the study of how people interact with
  computer systems to perform tasks. It does this
  in order to isolate design features that match
  the system to the needs of the user.
• It is no use designing a system for one group of
  people performing a set of tasks and expecting a
  different group to use it successfully to perform
  different tasks in a different setting
• A Practical Introduction to the Human Computer
  Interface - Stephen Hill

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Outcomes

• At the end of this session you will appreciate
• That HCI is concerned with people, systems and
  tasks
• There are guidelines, such as Nielsons
  heuristics to help produce a better design
• There are 3 main types of user
• Novice
• Expert
• Occasional

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Aspects of HCI

• HCI is mainly concerned with
• PEOPLE
• SYSTEMS
• TASKS

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People

• Need to consider the familiarity and expertise
  that the user has with regard to the task and the
  technology and how these factors interact to
  affect system use.

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Types of User

• There are 3 main types of user
• NOVICE
• EXPERT
• OCCASIONAL
• Activity
• List the software programmes that you believe you
  are an expert or novice at using and which ones
  do you use you occasionally

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Novice Users (1)

• New to the task, the system and/or technology
• Learnability
• How easy is it to learn?
• How easy is it to forget?
• How easy is it to re-learn?
• Training
• Paper-based
• On-line
• Human

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Expert Users

• Thoroughly familiar with the task, the system
  and/or technology
• Power users require
• Ways to achieve commonly performed tasks quickly
• Ability to customise and automate functions
• Support for learning advanced features
• Understanding of how the system achieves things

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Occasional Users

• Make intermittent use of the task, the system
  and/or technology
• They may be overly confident
• They may behave as experts for part of the system
  and novices for other parts
• They require reminding not teaching

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System Use

• Much of human reasoning is based on induction
• If something worked before in a similar
  situation, then it might work this time
• Many novice users will try commands from other
  software they have used in the past
• Consistency
• Wording
• Location of objects
• Colour schemes

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Text or Icons?

• Are icons preferable to words?
• Which convey meaning better?
• A traffic sign for a slippery road that displays
  an iconic representation works better than a sign
  saying slippery road, because there is less
  data to process, but only if the sign is
  recognised.

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Screens and Menus (1)

• Guidelines for designing a sequence of screens (a
  dialogue)
• 1. Use simple and natural dialogue
• 2. Speak the users language
• 3. Minimise users memory load
• 4. Be consistent
• 5. Provide feedback

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Screens and Menus (2)

• 6. Provide clearly marked exits
• 7. Provide shortcuts
• 8. Meaningful error messages
• 9. Use error prevention
• Your job as a designer is to keep these in mind

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Screens and Menus (3)

• Guidelines for designing a screen
• 1. Minimise amount of displayed data
• 2. Highlighting only used to draw attention
• 3. Standardise screen layouts
• 4. Group similar items
• 5. Use graphical output of numeric data
• 6. Use colour conservatively

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Screens and Menus (4)

• Menu structures
• Linear
• Series of choices
• Can all be presented together
• Hierarchical
• Tree structure
• Networked
• Multiple routes

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Nielsens Heuristics (1)

• Visibility of system status
• Match between systems and the real world
• User control and freedom
• Consistency and standards
• Error prevention

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Nielsens Heuristics (2)

• Recognition rather than recall
• Flexibility and efficiency of use
• Aesthetic and minimalist design
• Help users recognise, diagnose and recover from
  errors
• Help and documentation
• http//www.useit.com/papers/heuristic/heuristic_li
  st.html