Usability - PowerPoint PPT Presentation

1 / 26
About This Presentation
Title:

Usability

Description:

Usability & Design I 13th February – PowerPoint PPT presentation

Number of Views:130
Avg rating:3.0/5.0
Slides: 27
Provided by: acu66
Category:
Tags: usability | what

less

Transcript and Presenter's Notes

Title: Usability


1
Usability Design I
  • 13th February

2
Effective Web Design
  • Introduction to usability issues
  • Evaluation and analysis of web-sites

3
What is Usability?
  • Usability is NOT
  • Just common sense
  • all art (and no science)
  • stumbled onto by accident
  • tacked on at the end
  • free
  • Usability IS
  • intuitive, safe, error-free, enjoyable
  • best designed in from the beginning
  • best achieved by knowing your users
  • The best predictor of customer satisfaction
  • The next competitive frontier

4
What is Usability?
  • Usability can be defined as
  • the capacity to be used by humans easily and
    effectively where,
  • easily to a specified level of subjective
    assessment
  • effectively to a specified level of human
    performance (Shackel, 1990)
  • Usability affords the user easy access to the
    products functions

Usability Issues
5
Users
User Groups
Age
Computer skills knowledge
Disabilities
Cultural
6
Nielsens Heuristics
  • Nielsen defined 10 usability principles that can
    be applied to any system, although frequently
    used for web applications
  • Similar in aim to usability goals, except
    slightly more prescriptive
  • Used mainly as the basis for evaluating systems
  • Provide a framework for usability evaluation

7
Nielsens Heuristics
8
Nielsens Heuristics
  • Visibility of system status
  • Always keep users informed about what is going
    on, -gt provide appropriate timely feedback within
    reasonable time
  • e.g. when screen button clicked on provides sound
    or red highlight feedback

ccclichhk
9
Nielsens Heuristics
  • Match between system and the real world
  • Speak the users language
  • Dont use system oriented terms
  • Use real world conventions to make information
    appear in a natural and logical order? Use a
    technique called mapping Relationship between
    controls and their movements and the results in
    the world

10
Nielsens Heuristics
  • Why is this a poor mapping of control buttons?
  • Why is this a better mapping

11
Nielsens Heuristics
  • User control and freedom
  • Provide ways of allowing users to easily escape
    and navigate to/from places they unexpectedly
    find themselves e.g.
  • page forward / backward
  • hold
  • cancel
  • end / stop
  • help
  • resume
  • undo

12
Nielsens Heuristics
  • Consistency and standards
  • Avoid making users wonder whether different
    words, situations or actions means the same thing
  • Design interfaces to have similar operations and
    use similar elements for similar tasks
  • Main benefit is consistent interfaces are easier
    to learn, use and remember

13
Nielsens Heuristics
  • Follow platform conventions
  • Avoid confusion over whether different words,
    situations, or actions mean the same thing to
    user
  • No custom link colours. They may conflict with
    rest of Web and make site hard to use.
  • Web "standards"
  • Follow HTML specifications
  • Deviations from the standards results in
    unusable features creeping in

14
Nielsens Heuristics
  • 5. Help users recognise, diagnose and recover
    from errors
  • Use plain language to describe the nature of the
    problem and suggest a way of solving it
  • Careful design is better than good error messages
  • prevents problems from occurring in the first
    place

15
Nielsens Heuristics
  • 6. Recognition rather than recall
  • Make objects, actions, and options visible.
  • Dont force user to recall information
  • Instructions should be visible or retrieved
    easily when needed.
  • From point of view of the Web, this heuristic is
    closely related to system status
  • Users wont get lost if they can see where they
    are by looking at clues given by on current page.
  • No need to recall their path to the home page.
  • Good labels descriptive links are essential for
    recognition.
  • Use images for links, but they need to be well
    designed.

16
Nielsens Heuristics
  • Error prevention
  • Prevent them occurring in first place if
    possible
  • Key question Does the system prevent users from
    making serious errors, and if they do make an
    error, does it permit them to recover easily

17
Nielsens Heuristics
  • 8. Flexibility and efficiency of use
  • Provide accelerators that are invisible to
    novice users, but allow more experienced users to
    carry out tasks more quickly
  • Use accelerators (keyboard shortcuts)
  • Web Browser provides good accelerators e.g.
    bookmarks
  • Design for effective book-marking
  • contents of site can easily be linked to
  • users create specialized views of a site for
    specific tasks

18
Nielsens Heuristics
  • 9. Aesthetic and minimalist design
  • Avoid using info that is irrelevant or rarely
    needed
  • No irrelevant or rarely needed information in
    dialogues -gt diminishes visibility
  • Extraneous information on a page distracts user
    slows them down.
  • Use progressive levels of detail.
  • Support different uses of content. No brochures.

19
Nielsens Heuristics
  • 10. Help and documentation
  • Provide information that can be easily searched
    and provides help in a set of concrete steps that
    can easily be followed
  • Better if the system can be used without
    documentation
  • it may be necessary to provide help and
    documentation
  • Make it easy to search, focused on the user's
    task,
  • list concrete steps to be carried out, and not
    too large.

20
Pros and Cons Heuristic Evaluation
  • Advantages
  • detects both major (42) and minor (32) problems
    in UI
  • more effective than single specialist
  • can be used on designs
  • realistic approach
  • severity rating helps to set priorities
  • Disadvantages
  • groups can develop their own bias
  • doing it properly is not that cheap
  • new technologies (Web, Multimedia, Virtual
    Reality) may have specific problems not covered
    by The Heuristics

21
Analyse this using Nielsens Heuristics
22
Analyse this using Nielsens Heuristics
23
Analyse this using Nielsens Heuristics
24
Analyse this using Nielsens Heuristics
25
Analyse this using Nielsens Heuristics
26
References
  • Shneiderman, B. Plaisant, C. (2005) Designing
    the User Interface
  • Preece, J. et al. (2002) Interaction Design
  • Benyon, D. et al (2005) Designing Interactive
    Systems

References
Write a Comment
User Comments (0)
About PowerShow.com