Heuristic Evaluation and Discount Usability Engineering Taken from the writings of Jakob Nielsen –...

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