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USABILITY

USABILITY. Based on a lecture by Raino Vastamäki, Research Director Adage Oy in Kiljava on May 2003. Definition. ISO 9241-11

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USABILITY

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  1. USABILITY Based on a lecture by Raino Vastamäki, Research DirectorAdage Oy in Kiljava on May 2003

  2. Definition ISO 9241-11 • UsabilityThe extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.

  3. Why the users are so helpless? 1. Most of the human behavior is automated and unconscious • Example: We see first • Image before text • Movement • Large before small • Dark before light • Color before black and white • Saturated and warm colors • Strange before familiar • Unexpected things • Strong contrasts...

  4. N Z K M N M Z N Z N K K K Z M N Z M Z N K N Z N Z K M N M Z N Z N K KK Z M N Z M Z N K N Z N Z K M N M Z N Z N K K K Z M N Z M Z N K N Z N Z O M N M Z N Z N O O O Z M N Z M Z N O N Z

  5. Why the users are so helpless? 1. Most of the human behavior is automated and unconscious • Examples of websites • www.afl-cio.org • www.lo.se 2. Perception is fragmented and constructed

  6. Designer’s model

  7. Perceptual experience

  8. Projection on primary visual cortex

  9. Why the users are so helpless? 3. The users see only the interface, they don’t see the system as a whole 4. What is obvious for designers is strange for the user 5. The users are unfamiliar with the organization and the used terminology • Example of a website • www.sonera.com

  10. Why the users are so helpless? 6. Different user interfaces operate in different ways - sometimes even the same interfaces are not consistent • Example of a website • www.yle.fi 7. The fonts are too small • Minimum size 11–12 pt • Use high contrasts • Use lower case (abc) not upper case letters (ABC) • Enable the user to change text size • Don’t use red and green of same saturation together

  11. Designing usability • ”The user interface is not the paint put on at the end of the project, but the steel frame on which to hang the details”Ben Shneiderman,Designing the User Interface 1987

  12. -Discussions -Meetings -Interviews -Questionnaires -Log information -Usability evaluations of existing products Defining users Task analysis Context analysis Definition of usability requirements Website development Defining requirements Preliminary design Iterative planning -Iterations -Usability tests -Heuristic evaluations -Cognitive walkthroughs -Guidelines, standards, principles -Style guides -Design rationale Designing the general structure etc. Navigation maps Designing details Prototypes Realization Product -Usability tests Testing -Interviews -Questionnaires -Observation -Log information Product in use Launch

  13. Visibility of system status Match between system and the real world User control and freedom Consistency and standards Error prevention Recognition rather than recall Flexibility and efficiency of use Aesthetic and minimalist design Help users recognize, diagnose, and recover from errors Help and documentation www.useit.com/papers/heuristic/ The usability heuristicsJacob Nielsen 1994

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