Transcript mwwork

Museums and the Web 2001
Workshop
Conducting a Heuristic Evaluation
of a Museum Web Site
to Improve its Usability
David Farkas
University of Washington, College of Engineering
Werner Schweibenz
University of Saarland, Dept. of Information Science
Overview
1 Usability - Definitions
2 Usability Engineering for the Web
3 Methods for Usability Engineering
4 Heuristics for Evaluation
5 Application of the Findings
6 Conclusion
Museums & the Web 2001
2
Usability - Definitions
"Usability is the measure of the quality of the
user experience when interacting with
something – whether a web site, a traditional
software application, or any other device the
user can operate in some way or another."
(Jakob Nielsen)
ISO 9241 Ergonomic requirements for office
work with visual display terminals (VDTs)
Museums & the Web 2001
3
Usability and functionality
• Usability and functionality are attributes of a product.
• Functionality refers to what you can do with the
product. Usability refers to how users actually use the
product.
• "The functionality exists. But building functionality
into a product, however, doesn't guarantee that people
will be able to use it."
(Dumas & Redish)
• "A product by itself has no value; it has value only
insofar as it is used. Use implies users."
(Dumas & Redish)
Museums & the Web 2001
4
2 Usability Engineering for the Web
• The Web is a complex graphical user interface but has
to be instantly usable.
• "Usability rules the Web. Simply stated, if the
customer can’t find a product, then he or she will not
buy it." (Nielsen 2000)
• In the context of the World Wide Web, "usability
refers to how easy it is to find, understand and use the
information displayed on a Web site." (Keevil 1998)
Museums & the Web 2001
5
The Situation on the Web
• Nielsen estimated that there will be about 10 billion
Web pages on the Internet by the Year 2001.
• Traditional user testing (deluxe usability) in the
laboratory is too expensive to do.
• Discount usability engineering is our only hope. We
need methods simple enough that people can do
usability work, fast enough that people will take the
time, and cheap enough that it's still worth doing.
• Heuristic evaluation is the right tool for discount
usability engineering on the Web.
Museums & the Web 2001
6
3 Methods for Usability Engineering
• Usability engineering is a set of methods to design
user-friendly products.
• There are a wide variety of methods.
• Expert-focused (analytical) methods, e.g. heuristic
evaluation with experts as "surrogate users."
• User-focused (empirical) methods, e.g. laboratory
tests with the thinking aloud method and actual users.
• A combination of heuristic evaluation and laboratory
testing provides the greatest value from each method.
Museums & the Web 2001
7
Heuristic Evaluation
• "Heuristic evaluation is a way of finding usability
problems in a design by contrasting it with a list of
established usability principles." (Nielsen 1997)
• Advantage: five evaluators can find some 75 per cent
of the usability problems
• Disadvantage: experts cannot step back behind what
they already know ("surrogate users")
Museums & the Web 2001
8
Laboratory Testing
with Thinking Aloud
• Thinking aloud "is the most fundamental usability
method and is in some sense irreplaceable, since it
provides direct information about how people use
computers and what their exact problems are with the
concrete interface being tested."
(Nielsen)
• Advantage: tests supply a huge amount of qualitative
data that show how actual users handle the product.
• Disadvantages: tests take place in a laboratory situation and a lot of equipment and coordination is
necessary to conduct the test.
Museums & the Web 2001
9
Usability Lab
working place of
the participant
thinking aloud
video camera
recording
the actions on
the screen
participant
computer screen
and keyboard
microphone
mixing console
for the video
cameras
video recorder
and tv for
recording
notes
test manager
video camera recording the actions of
the participant
Museums & the Web 2001
technical
10
assistant
Usability Engineering Lifecycle
"Usability engineering is not a one-shot affair where
the user interface is fixed up before the release of the
product. Rather, usability engineering is a set of
activites that ideally take place throughout the
lifecycle of the product, ..."
(Nielsen)
Museums & the Web 2001
11
The Web usability engineering lifecycle
Web site
heuristic
evaluation
detected usability problems,
severity rating
developing
test material
suggestions
for the
redesign
questionnaires
analysing the data
of user tests and
heuristic evaluation
data from
the user
tests
Museums & the Web 2001
test tasks
user tests with
thinking aloud
12
4 Heuristics for Evaluation
• Simple heuristics, e.g. 10 basic heuristics of
Molich & Nielsen (1990)
• Complex checklists, e.g. Keevil‘s Usability
Index (1998)
• Complex heuristics, e.g. Heuristics for Web
Communication (2000)
Museums & the Web 2001
13
Heuristics of Molich & Nielsen
•
•
•
•
•
•
•
•
•
•
Simple and natural dialogue
Speak the user´s language
Minimize the user´s memory load
Consistency
Feedback
Clearly marked exits
Shortcuts
Precise and constructive error messages
Prevent errors
Help and documentation
Museums & the Web 2001
14
The Keevil Usability Index
The Usability Index consists of 203 questions arranged
in five categories:
• Finding the information: Can you find what you want?
• Understanding the information: After you find the
information, can you understand it?
• Supporting user tasks: Does the information help you
perform a task?
• Evaluating the technical accuracy: Is the technical
information complete?
• Presenting the information: Does the information look
like a quality product?
Museums & the Web 2001
15
Findings of the Usability Index
• The usability index is calculated from the total
number of 'yes' answers divided by the total numbers
of 'yes' and 'no' answers.
• The 203 questions leave room for interpretation.
• In the Saarland Museum study, the Keevil Usability
Index for 15 evaluators ranged from 29% to 55%, the
arithmetic mean being 47%. The deviation is due to
the bias of the evaluators in interpreting the questions.
Museums & the Web 2001
16
The Heuristics for Web
Communication
• The Heuristics for Web Communication are a set of
five heuristics with the scope on information-oriented
Web sites.
• They were developed for an International Summer
Workshop Exploring a Communication Model for Web
Design, Seattle, WA, July 10-17, 1999.
• They cover all important aspects of Web communication: displaying information, navigation, text
comprehension, role playing (i.e. author-reader
relationship), and data collection for analyzing
interaction.
Museums & the Web 2001
17
The Heuristics for
Web Communication
• Advantages: they are both design-oriented, i.e. they
can be used as guidelines for designing a prototype,
and evaluation-oriented, i.e. they can be used for
evaluating an existing Web site. Their function in the
design process is both idea-generating and
troubleshooting.
• Disadvantages: they are applicable to informationoriented Web sites only; and they are complex and
that it takes some time and effort to learn how to apply
them.
Museums & the Web 2001
18
The Heuristics for
Web Communication
• Special Issue of the Journal of Technical
Communication, August 2000, Vol. 47, No. 3,
available in print and online.
• Quicklists for Web Communication. In:
Technical Communication Online, August
2000, Vol. 47, No. 3., Internet, URL
http://www.techcomm-online.org/shared/
special_col/quicklists/menu.htm
Museums & the Web 2001
19
Heuristic Evaluation of Web Sites
A heuristic evaluation can be conducted in several steps:
• Forming teams of 4 or 5 expert as evaluators
• Getting to know the Web site (ca. 15 min browsing)
• Individual evaluation of the Web site by each expert
using one of the heuristics (ca. 60 to 90 min)
• Severity rating of uncovered problems in teams (ca.
60 to 90 min)
• Presentation of the findings of all the involved teams
• Collecting the findings and writing an evaluation
report
Museums & the Web 2001
20
Severity Rating of the Findings
Rating categories according to Nielsen:
• 0 I don't agree that this is a usability problem at all
• 1 Cosmetic problem only: need not be fixed unless
extra time is available on project
• 2 Minor usability problem: fixing this should be
given low priority
• 3 Major usability problem: important to fix, so
should be given high priority
• 4 Usability catastrophe: imperative to fix this before
product can be released
Museums & the Web 2001
21
Findings of the Heuristics
• The heuristics detect a great number of usability
problems: inconsistent use of link colors, no text
messages for graphic links, complicated sentences,
deficits in page structure and organization, lack of
informative titles, overuse of bold and italics,
meaningless animation, flaws in the author-reader
relationship etc.
• These problems are real usability problems but might
not observable in user testing, because average users
do not realize that they cause problems because they
lack the background knowledge in Web design.
Museums & the Web 2001
22
5 Application of the findings
The findings of the heuristic evaluation
can be used
• for a redesign of the Web site.
• for generating ideas for the further
development of the Web site.
• for developing test tasks for laboratory tests
with actual users.
Museums & the Web 2001
23
6 Conclusion
• The Heuristics for Web Communication proved
to be applicable tools for heuristic evaluation.
• The heuristics support a structured evaluation
and help both to find and to solve usability
problems.
• In contrast to simple checklists, they give the
evaluators some scope for interpretation while
offering guidence at the same time.
• A heuristic evaluation can be complete by a
few evaluators in a few days.
Museums & the Web 2001
24
Thanks for listening.
Any questions or comments?
For information on the heuristics please contact
David Farkas, [email protected]
Fon: 206-685-8659
For information on evaluation please contact
Werner Schweibenz, [email protected]
Fon: +49-681-302-3542
Museums & the Web 2001
25