USABILITY

Dialog on - Usability Düsseldorf 1.11.2003 / PV page 1

USABILITY

Based on a lecture by

Raino Vastamäki, Research DirectorAdage Oy

in Kiljava on May 2003


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.


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...


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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


Designer’s model


Perceptual experience


Projection on primary visual cortex



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



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


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


Defining usersTask analysisContext analysisDefinition of usability requirements

Defining usersTask analysisContext analysisDefinition of usability requirements

PrototypesPrototypes

Navigation mapsNavigation maps-Iterations-Usability tests-Heuristic evaluations-Cognitive walkthroughs-Guidelines, standards, principles-Style guides-Design rationale

-Iterations-Usability tests-Heuristic evaluations-Cognitive walkthroughs-Guidelines, standards, principles-Style guides-Design rationale

-Usability tests-Usability tests

-Interviews-Questionnaires-Observation-Log information

-Interviews-Questionnaires-Observation-Log information

Product in use

Product in use

Defining requirementsDefining requirements

Preliminary designPreliminary design

Iterative planning

Iterative planning

Designing thegeneral structure etc.

Designing thegeneral structure etc.

Designing detailsDesigning details

TestingTesting

LaunchLaunch

RealizationRealization

ProductProduct

Website development -Discussions-Meetings-Interviews-Questionnaires-Log information-Usability evaluations of existing products

-Discussions-Meetings-Interviews-Questionnaires-Log information-Usability evaluations of existing products


The usability heuristicsJacob Nielsen 1994

• 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/

USABILITY

Documents

Transcript of USABILITY