Transcript PowerPoint notes for Heuristic Evaluation from Jakob Nielsen's writings

Heuristic Evaluation and
Discount Usability Engineering
Taken from the writings of Jakob
Nielsen – inventor of both
Heuristic Evaluation
• Context – part of iterative design
• Goal – find usability problems
• Who – small set of evaluators
• How – study interface in detail, compare to
small set of principles
Ten Usability Heuristics
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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
How to Conduct a Heuristic
Evaluation
• More than one evaluator to be effective.
• Each evaluator inspects the interface by
themselves
• General heuristics may be supplemented
• Results can be oral or written
• Evaluator spends 1-2 hours with interface
• Evaluator goes through interface > 1 time
• Evaluators may follow typical usage scenarios
• Interface can be paper
Different Evaluators Find
Different Problems
Number of Evaluators
Heuristic Evaluation Results
• List of usability problems
– With principle violated
– With severity
• NOT fixes
• May have debriefing later to aid fixing
• Discount usability
Usability Problem Location
• Single Location
• Two/Several Locations
• Overall Structure
• Something Missing
Severity
• Help focus repair efforts
• Help judge system readiness
• Factors in Severity:
– Frequency
– Impact
– Persistence
– Market impact
• Scale severity to a number
• May wait on severity
H.E. Complementary w/
Usability Testing
• Each will find problems that the other will miss
• H.E. Weakness – finding domain specific
problems
• Don’t H.E. and Usability Test same prototype
version
Discount Usability Engineering
• “It is not necessary to change the fundamental way
that projects are planned or managed in order to
derive substantial benefits from usability inspection”
• 6% of project budget on usability
• 18% of respondents used usability evaluation
methods the way they were taught
More Discount Usability Engineering
• Cost projection to focus on usability may be
reduced
• “Insisting on only the best methods may result
in having no methods used at all”
• 35% of respondents used 3-6 users for
usability testing
• Nielsen and others suggest 50-1 ROI
Elements of Discount Usability
Engineering
• Scenarios
• Simplified Thinking Aloud
• Heuristic Evaluation
Scenarios
• Take prototyping to extreme – reduce functionality
AND number of features
• Small, can afford to change frequently
• Get quick and frequent feedback from users
• Compatible with interface design methods
Simplified Thinking Aloud
• Bring in some users, give them tasks, have
them think out loud
• Fewer users in user testing
Heuristic Evaluation
• Fewer principles etc to apply
• Compare interface to previous version or
competitor
• Ensure tasks are parallel
• “Within Subjects” recommended
• Counter balance order
Stages of Views of Usability in
Organizations
1.
2.
3.
4.
5.
6.
7.
8.
Usability does not matter.
Usability is important, but good interfaces can surely be
designed by the regular development staff as part of their
general system design.
The desire to have the interface blessed by the magic wand of
a usability engineer.
GUI/WWW panic strikes, causing a sudden desire to learn
about user interface issues.
Discount usability engineering sporadically used.
Discount usability engineering systematically used.
Usability group and/or usability lab founded.
Usability permeates lifecycle.
End Nielsen insert for Chapt 4