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Remove Stumbling Blocks by Usability Testing
Help visitors navigate your Web site by removing stumbling blocks in advance.
A well-planned trial run can prevent problems before they arise.
Shopping the other day on garden.com, I
selected one item to purchase and continued browsing. After considering a few
more items, I decided I'd shopped long enough.
I looked for a link labeled "check out," but there was no such link
on the page. I glanced high and low for the ubiquitous shopping-cart symbol, but
it was not to be found. Then I carefully studied every link and graphic on the
page, trying to find a way to buy the item I had selected. No go. After
continuing to bumble around the site, I finally discovered that garden.com's
term for shopping cart is "wheelbarrow" and that there is in fact a
wheelbarrow text link on each page.
Obvious? I think not.
Note: After this article was written, garden.com was acquired by
Burpee seeds, and it now provides a standard shopping cart icon and text.
I've noticed a strong new interest in usability testing, thanks to the growth
of the Web. If an e-shopper gets lost in a maze of clicks and doesn't make a
purchase, that's a big problem. If a visitor decides not to register at a Web
site due to the lack of a privacy statement, that's a problem too. With proper
preparation, usability testing can isolate these costly problems and point the
way to solving them.
In its simplest form, usability testing requires only three ingredients: an
application or Web site, a usability tester, and an observer. The usability
tester navigates the application or Web site as a real user would, and the
observer identifies usability problems by observing the tester's efforts. Add a
few ingredients -- more testers, more observers, a facilitator, a set of
well-crafted test scenarios, and some video equipment -- and you've got a recipe
Note that usability testers are not the same as software testers whose job is
to find bugs in the program. These testers' sole concern is the functionality of
the application or Web site.
Careful planning helps immensely in getting beneficial results from this kind
of test. The key is to have a clear understanding of the target users and their
goals in using the application or Web site. With that understanding, you can
choose a representative set of users and create an intelligent set of test
Five or six testers should be plenty if you plan carefully to ensure that
they represent the user base. Pick testers who represent the range of knowledge
and abilities of the people who will use the application. Usability testing can
help you understand how easy it is for beginners to start using the application
or Web site. It can also help you see how well users make the transition from
beginner to intermediate. And it can show you how well your power users fare.
During the planning stage, you should prepare, try out, and refine test
scenarios. A test scenario describes a particular task and asks the tester to
accomplish the task using the application or Web site. The set of scenarios
should provide sufficient challenge and time to uncover any significant
struggles with the user interface. By trying them out ahead of time, you can
make sure they are clearly written and are not too much of a challenge for the
allotted test time.
Make sure you select a facilitator with excellent people skills. The
facilitator's most important job is to make the testers feel comfortable, to
help them understand the objectives of the test, and to clarify their role in
usability testing. The facilitator should explain that the purpose of the test
is to uncover problems with the software's usability -- not to test the tester.
Be kind to your testers by not keeping them any longer than is absolutely
necessary. Limit their test time to 30 minutes if possible. Plan time in the
schedule for debriefing each tester and then for debriefing the observers after
each test session.
If possible, get everyone on the development team involved as observers.
After they've finished watching the users struggle through the test scenarios,
they'll be your best allies in making improvements.
During a trial, the tester attempts to follow one or more scenarios.
Observers watch and take notes on how easily tasks are accomplished; they note
the tester's emotional responses as well. The facilitator should ask the
tester to think out loud; this makes observers aware of assumptions users tend
to make about the user interface.
Observers should try to note the exact user-interface features applied to
each task and the time needed to finish. They should also note the problems
encountered and the number and type of hints given to help resolve the
The facilitator should make sure the test moves along according to schedule.
Afterward the facilitator will debrief the tester, relaying questions from the
observers and asking for general feedback, and will then debrief the observers
after the tester leaves. Immediate debriefing is desirable. The observers' and
testers' findings should be consolidated while the test is still fresh.
After all testers have been observed, the facilitator may lead an additional
work session with the observers to analyze and report the usability test
findings. If a videotape was made, the observers might want to review portions
Time, cost, and videotape
You'll need to decide if it's worth the extra effort and cost to videotape
the test sessions. Tapes can come in handy for comparing conflicting
observations. Also, seeing is believing. So if you anticipate needing to
convince management, you'll definitely want to tape the test sessions. Put
together a persuasive set of excerpts from the tape to back up your test
While a standard video camera will suffice, you can also rent or buy
specialized usability testing equipment. Typically, this specialized equipment
will allow you to videotape the software in action and superimpose the tester's
face -- with its positive and negative expressions -- in a corner of the
display. If the usability testing equipment is installed in a permanent testing
facility, observers may be able to work behind one-way mirrors so that the
tester isn't distracted by the feeling of being watched.
People often assume that usability testing costs a great deal of money.
Building a permanent usability-testing lab can cost tens or even hundreds of
thousands of dollars, and even a portable lab can cost many thousands of
dollars. But if cost is an issue, skip the technology and focus on what's
important: a representative set of testers, some carefully crafted test
scenarios, and a watchful, objective observer or two.
You don't have to expend a great deal of time on usability testing either. If
time is an issue, examine only the parts of the design you're least confident
about. Note potential trouble spots as the project is coming together. If you
design these problem areas incorrectly, they will cost you more in the long run
in redesign, recoding, and retesting. Making sure of them early in the
process will save the cost of rework late in development or during the next
Usability tests do a great job of showing what's not working in a design, but
don't get caught in the trap of asking testers to suggest design improvements.
Testers are not designers, and their answers will be wrong. Use the test results
to expose bugs, but don't go overboard. If you derive the design from testing,
you'll see small improvements, but these amendments will come at the expense of
innovation and creativity.
Would a usability test have prevented my difficulty in finding garden.com's
check-out link? Probably. Is completing the purchase an important task for this
Web site? Absolutely. Would others have similar problems figuring out how to
check out? If so, then a carefully crafted test scenario would certainly have
caught the problem.
Home Articles We've Written Usability Testing