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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• 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. Usability does not matter.
2. Usability is important, but good interfaces can surely be designed by the regular development staff as part of their general system design.
3. The desire to have the interface blessed by the magic wand of a usability engineer.
4. GUI/WWW panic strikes, causing a sudden desire to learn about user interface issues.
5. Discount usability engineering sporadically used.
6. Discount usability engineering systematically used.
7. Usability group and/or usability lab founded.
8. Usability permeates lifecycle.
End Nielsen insert for Chapt 4