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Usability Engineering

     Manoj Chawla
Agenda
•   What Is Usability?
•   Generations of User Interfaces
•   The Usability Engineering Lifecycle
•   Usability Heu...
Definition
•   Learnability                      • Issues
     – Easy to learn                     – Users task
•   Effici...
Usability rules
•   Your best guess is not good enough
•   The user is always right
•   Users are not designers
•   Design...
Scenarios




            Source: Jakob Nielson
Generations of user interfaces
Generation     Hardware        Technology       Users           Advertising     User interf...
The lifecycle

•   Know the User                     •   Guidelines and Heuristic
•   Individual User Characteristics     ...
Heuristic evaluation
•   Graphic design and colour
•   Simple and natural dialogue
•   Speak the users language
•   Minimi...
Discount usability engineering
• User and task observation
   – Simple visits to customer locations, observe and be
     q...
Usability testing
•   Reliability                     •   Stages of a Test
•   Validity                             –   Pr...
Measuring subjective satisfaction
•   Pleasing      ________   Irritating
•   Complete      ________   Incomplete
•   Coop...
Methods beyond testing
•   Observation
•   Questionnaires and Interviews
•   Focus Groups
•   Logging Actual Use
•   Combi...
International user interface
• May or may not involve translation
• Icons
   – Resemblance icons e.g. envelope for mail
  ...
The future
•   Speech input/output
•   Individualised interaction
•   Increased use of graphics
•   Dialogues designed by ...
Actions
• Recognise the need for usability
• Provide senior management support
• Devote specific resources to usability
  ...
Usability trade-offs
• Include accelerators for experts
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Usability Engineering

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Transcript of "Usability Engineering"

  1. 1. Usability Engineering Manoj Chawla
  2. 2. Agenda • What Is Usability? • Generations of User Interfaces • The Usability Engineering Lifecycle • Usability Heuristics • Usability Testing • Usability Assessment Methods beyond Testing • Interface Standards • International User Interfaces • Future Developments
  3. 3. Definition • Learnability • Issues – Easy to learn – Users task • Efficiency of Use – Users individual – Expert users steady level of characteristics performance – User differences • Memorability • Age, gender, reasoning ability – Easy to remember – Experience with the system • Few and No catastrophic Errors – Experience with computers – Minimise frequency of errors in general • Subjective Satisfaction – Experience with the task – How pleasant it s to use the domain system
  4. 4. Usability rules • Your best guess is not good enough • The user is always right • Users are not designers • Designers are not users • Vice presidents are not users • Less is more • Details matter • Help doesn’t always help • Usability engineering is a process
  5. 5. Scenarios Source: Jakob Nielson
  6. 6. Generations of user interfaces Generation Hardware Technology Users Advertising User interface Image paradigm -1945 Electro/Mechani Blinking lights & Inventors None None cal cards 1945-1955 Vacuum tubes Typewriter Experts/pioneers Calculator Programming batch 1955-1965 Transistors Line oriented Technocrats Information Command terminals processor languages 1965-1980 Integrated Full screen Specialised Mechanisation Hierarchical Circuits terminal groups w/o e.g. bank tellers menus and form knowledge fill-in 1980-1995 VLSI PC Professionals/Ho Personal WIMP bbyists productivity tool 1995-? Networked PC’s Easily portable Everybody Computer as Non command with cellular appliance based interfaces modem
  7. 7. The lifecycle • Know the User • Guidelines and Heuristic • Individual User Characteristics Evaluation • Prototyping • Task Analysis • Scenarios • Functional Analysis • Interface Evaluation • The Evolution of the User – Severity Ratings • Competitive Analysis • Iterative Design • Goal Setting • Capture the Design Rationale • Financial Impact Analysis • Follow-Up Studies of Installed • Parallel Design Systems • Meta-Methods • Participatory Design • Prioritising Usability Activities • Coordinating the Total • Be Prepared Interface
  8. 8. Heuristic evaluation • Graphic design and colour • Simple and natural dialogue • Speak the users language • Minimise the users memory load • Consistency • Feedback • Clearly market exits • Shortcuts • Good error messages • Prevent errors • Help and documentation
  9. 9. Discount usability engineering • User and task observation – Simple visits to customer locations, observe and be quiet let the users work normally with out interference • Scenarios – Scenarios are prototypes with reduced functionality and features • Simplified thinking aloud – Test user allowed to use the system while being asked to think aloud. This allows the observer not just what but why
  10. 10. Usability testing • Reliability • Stages of a Test • Validity – Preparation • Test Goals and Test Plans – Introduction • Test Plans – Running the Test – Debriefing • Test Budget • Performance Measurement • Pilot Tests • Thinking Aloud • Getting Test Users • Constructive Interaction • Novice versus Expert Users • Retrospective Testing • Between-Subjects versus Within-Subjects Testing • Coaching Method • Choosing Experimenters • Usability Laboratories • Ethical Aspects of Tests with • Cameraless Videotaping Human Subjects • Portable Usability Laboratories • Test Tasks • Usability Kiosks
  11. 11. Measuring subjective satisfaction • Pleasing ________ Irritating • Complete ________ Incomplete • Cooperative ________ Uncooperative • Simple ________ Complicated • Fast to use ________ Slow to use • Safe ________ Unsafe
  12. 12. Methods beyond testing • Observation • Questionnaires and Interviews • Focus Groups • Logging Actual Use • Combining Logging with Follow-Up Interviews • User Feedback • Choosing Usability Methods • Combining Usability Methods
  13. 13. International user interface • May or may not involve translation • Icons – Resemblance icons e.g. envelope for mail – Reference icons e.g. depicts some object – Arbitrary icons – e.g. meaning by convention • Guidelines – Characters – more than ASCII character set – Numbers & currency – Time and measurement units • Resource separation – Separate the interface and the system functionality • Multi-local interfaces – Flexibility for different users to communicate
  14. 14. The future • Speech input/output • Individualised interaction • Increased use of graphics • Dialogues designed by users • Increase computer knowledge • System adapts to user • Natural language • Self explanatory systems without manuals • Computer support for cooperative work
  15. 15. Actions • Recognise the need for usability • Provide senior management support • Devote specific resources to usability engineering • Integrate UE activities into various stages of development • Make sure the user interfaces are subjected to user testing
  16. 16. Usability trade-offs • Include accelerators for experts
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