"Studies by Forrester Research
estimate several costs of bad site design. The two
most striking are, 1) Losing approximately 50% of the potential
sales from a site as people can't find what they need, and 2) Losing repeat visits
from 40% of the users who do not return to a site when their first visit resulted in a
negative experience."
Website Usability
Guidelines from the National Cancer Institute's Guidelines to determine how usability
factors in to your website planning, development, and customer conversion.
Website Usability - Basic FAQ
What Is Usability?
Usability is the measure of the quality of a user's
experience when interacting with a product or system — whether a Web site, a software
application, mobile technology, or any user-operated device.
Usability is a combination of factors that affect the
user's experience with the product or system, including:
| Ease of learning |
How fast can a user who has never
seen the user interface before learn it sufficiently well to accomplish basic tasks?
|
| Efficiency of use |
Once an experienced user has learned
to use the system, how fast can he or she accomplish tasks?
|
| Memorability |
If a user has used the system before,
can he or she remember enough to use it effectively the next time or does the user have to
start over again learning everything?
|
Error frequency and severity
 |
How often do users make errors while
using the system, how serious are these errors, and how do users recover from these
errors?
|
| Subjective satisfaction |
How much does the user like using the system? |
• Links to Related Articles
Usability
and the Web: An Overview, by George Murray and Tania Costanzo, at the National Library
of Canada,
http://www.nlc-bnc.ca/9/1/p1-260-e.html
What Is
Usability?, by Jakob Nielsen,
http://www.zdnet.com/devhead/stories/
articles/0,4413,2137671,00.html
What Is Usability?,
by Environmental Systems Research Institute, Inc.,
http://www.esri.com/software/usability/whatisusability.html
Why Is Usability Important?
Research by User Interface Engineering, Inc., shows that
people cannot find the information they seek on Web sites about 60% of the time. This can
lead to wasted time, reduced productivity, increased frustration, and loss of repeat
visits and money.
Other sources report:
- "There are about 43 million Web sites, and no
one knows which ones are usable. The best sites we've found are usable only 42 percent of
the time, and none that we have studied are usable a majority of the time ...."
- Studies by Forrester Research estimate several costs
of bad site design. The two most striking are:
• Losing approximately 50% of the potential sales
from a site as people can't find what they need
• Losing repeat visits from 40% of the users who do
not return to a site when their first visit resulted in a negative experience
- Site design guru Jakob Nielsen reports:
"Studies of user behavior on the Web find a low
tolerance for difficult designs or slow sites. People don't want to wait. And they don't
want to learn how to use a home page. There's no such thing as a training class or a
manual for a Web site. People have to be able to grasp the functioning of the site
immediately after scanning the home page — for a few seconds at most."
• Links to Related Articles
Mazed and Confused, Sari
Kalin, CIO WebBusiness, http://www.cio.com/archive/webbusiness/040199_use.html
Spool of Thought,
Elizabeth Millard, in Business 2.0,
http://www.business2.com/articles/mag/0,1640,13190,ff.html
Failure
of Corporate Websites, Jakob Nielsen, Alertbox,
http://www.useit.com/alertbox/981018.html
Web-Site
Usability: Usability On The Web Isn't A Luxury, Jakob Nielsen and Donald A. Norman, in
InformationWeek, http://www.informationweek.com/773/web.htm
What Is the Difference
Between Usability Engineering and Usability Testing?
Usability engineering is a methodical approach to
producing a Web site or any user interface. It is a practical and systematic way to
deliver a product that works for users. Usability engineering involves several methods,
each applied at appropriate times, including gathering requirements, developing and
testing prototypes, evaluating design alternatives, analyzing usability problems,
proposing solutions, and testing a site (or other interface) with users.
Usability testing is part of the process of
usability engineering. Usability testing includes a range of methods for having users try
out a site (or other system). In a typical usability test, users perform a variety of
tasks with a prototype (or other system) while observers record notes on what each user
does and says. Typical tests are conducted with one user at a time or two users working
together. Testing may include collecting data on the paths users take to do tasks, the
errors they make, when and where they are confused or frustrated, how fast they do a task,
whether they succeed in doing the task, and how satisfied they are with the experience.
The goal of most usability testing is to uncover any problems that users may encounter so
those problems can be fixed.
• Links to Related Articles
Usability
Engineering for the Web, Keith Instone, World Wide Web Journal,
http://www.w3j.com/5/s3.instone.html
Usability Glossary,
Usability First,
http://www.usabilityfirst.com/glossary/glossary.taf
What Steps Are Involved in Usability?
• Getting Started — Planning the Web Site
The first step is to understand:
- why you are developing a site
- who should come to your site
- when and why those people might come
In answering these questions, you establish your
objectives for the site. The specific objectives depend, of course, on your organization
and your audience.
You should also think about usability objectives for the
site. General usability objectives are that a site must be:
- easy to learn
- efficient to use
- easy to remember on subsequent visits
- satisfying, with a minimum number of errors as users go
through the site
All the usability objectives are important for most
sites, but you may emphasize different ones for different audiences and situations. For
example, in a site that is aimed at members of the general public who may only visit once
in a while, you should build a site where almost no learning needs to take place to use it
efficiently.
• Collecting Data from Users
Because the design is to be based on user needs, data must be collected about those needs
and how well an existing Web site (if there is one) is meeting those needs. There are a
variety of ways to collect that data, including feedback forms and system metrics (log
data on an existing site), and usability testing of the existing site.
• Developing prototypes
It is easier for a user to react to an existing example than to theorize what would work
best. Useful results can be obtained by building a prototype site, with a minimum of text
content and no graphics, for a first round of usability testing. The prototype can then be
used to elicit user comments and observe the prototype's ability to lead the users through
the tasks they need to perform. It can be built on paper or with simple HTML.
• Collecting, writing, or revising
content
Based on what users need, you must put content into the site. As you consider
information that you already have, think about how useful and understandable it is.
Reading from a computer screen is slower than reading from paper. Most people want to
quickly scan information and read only small sections. If the information you have is in
long paragraphs, consider revising it. Break it into small chunks with many headings. Cut
out unnecessary words. Use lists and tables so people can find information quickly. Follow
these same guidelines when writing new information for the Web.
• Conducting usability tests
Usability testing is an iterative process. The goal of usability testing is to ascertain
what will help users accomplish their tasks and what may impede them. Using the prototype
as a starting point, the usability testers build a set of scenario tasks they will ask
users to attempt. As detailed information about user success is gathered and reported, the
prototype can be modified and additional aspects of that prototype tested.
Usability testing can be done inexpensively
or more formally, depending on the size and budget of the site under development. As the
testing team becomes more experienced, testing can be accomplished more quickly.
User Testing links at Usable Web
http://usableweb.com/topics/000878-0-0.html
• Continuing to assess the site after it is up
When the site has been implemented, it is incumbent on the developers or the owners of the
content to assess its performance by analyzing reports, usage logs, and other data sources
for the site and by continuing to gather user feedback on usability.
Log
Analysis links at Usable Web
http://www.usableweb.com/topics/000649-0-0.html
What Is a Usability Test Like?
The focus of a usability test is the user's experience
with a site. The site may exist only as a paper prototype, or it may be a real working
prototype or a site that has already been launched. The earlier you start to have users
try out the site, the faster and easier it will be to develop the site you want.
During a usability test, specialists working with the
designers and developers of the site watch users working through tasks with the site and
gather other feedback. The purpose is always to see what is working well and what is not
working well — with the goal of improving the site. Usability specialists manage the
test, work directly with the users, and take notes; designers, developers, and others also
observe — usually from an adjacent room or from a live video and audio stream —
and should also take notes.
Usability specialists gather all the notes, consolidate
and analyze them, and together with the designers and developers consider the problems
they saw and how to solve them. The result of usability testing is a set of
recommendations for improving the site.
• Links to Related Articles
What is
Strategic Usability? by The Usability Group,
http://usability.com/umi_what.htm
User Testing,
Seth Gordon, CNET Builder.com,
http://builder.cnet.com/webbuilding/pages/Graphics/Evaluation/
Users First,
Jakob Nielsen, ZD Net.com,
http://www.zdnet.com/devhead/stories/articles/
0,4413,2224316,00.html
Do I Need a Lab to Do Usability
Testing?
No. You can do usability testing in either a formal or
informal setting. In any type of setting, your methodology can also range from formal to
informal.
You can do effective usability testing in any of these
settings:
- a fixed laboratory having two or three connected rooms
outfitted with audio-visual equipment
- a conference room, or the user's home or work space, with
portable recording equipment
- a conference room, or the user's home or work space, with
no recording equipment, as long as someone is observing the user and taking notes
- remotely, with the user in a different location, as long
as the observer can monitor what the user is doing, listen to the user thinking aloud, and
interact with the user by computer or telephone during the session
For more on audio-visual equipment for recording
usability test sessions, see the lists of equipment for both fixed and portable labs in Usability Labs.
• Links to Related Articles
Usability
Labs: Our Take, in User Interface Engineering,
http://world.std.com/~uieweb/labs.htm
How Many Participants Are
Needed for a Usability Test?
It depends. A typical range is from five to 12 users in
each test. If each user works with you for an hour, that means one or two days of testing.
You might need only three people to help you find serious
problems, if you:
- are doing paper prototypes or are in early development
- plan several rounds of testing throughout development
- have a fairly homogenous user population
If you have different potential user groups (for example,
physicians, patients, researchers), try to include representatives of all these groups. If
you are likely to have users with a range of Web or computer experience, try to include
both less experienced and more experienced users. Those considerations may push the number
of people you need from three to six or nine or 12.
If you want to conduct formal quantitative testing on
your products or systems, you'll need more people to derive statistical results. For
diagnostic usability testing, five users are usually enough to uncover the major problems
in a product.
If you do iterative (repeated) usability testing over the
course of developing the Web site, many users will participate in testing one or another
version of the emerging site. Thus, while you may have fewer than 10 participants in each
usability test, you may have 15 to 30 people who have tested some version of the site
before it is launched.
• For more information on:
Different goals for usability testing (diagnostic,
comparative, verification), see How formal or
informal should usability testing be?
Deciding which type of test to conduct paper prototyping,
see Developing Prototypes
Needing only five people to find major problems, see
Jakob Nielsen, Why You Only Need To
Test With 5 Users, Alertbox, March 19, 2000,
http://www.useit.com/alertbox/20000319.html
Why 8 Or
Less Test Users Work, see User Interface Engineering, Eight Is More Than Enough,
http://world.std.com/%7Euieweb/eight.htm
How
Much Does It Cost to Do Usability Testing?
Cost depends, of course, on the size of the site, how
much you need to test, how many different types of users you anticipate having, and how
formal you want the testing to be.
Having a standard process and reusable materials makes
usability testing faster and less expensive. If you or your recruiting firm develop a
database of users, recruiting becomes less time consuming and, therefore, cheaper.
Consider these elements in budgeting for usability
testing:
- time to plan: identify issues to focus on in testing,
identify types of users to involve in testing, write a screening questionnaire to recruit
users, write scenarios for users to follow
- cost of recruiting: time of in-house person or payment to
a recruiting firm (often a good option)
- time of usability specialist to become familiar with the
site and of team to do a dry run to see how scenarios work with the site
- cost of renting laboratory space or a portable lab or
other videotaping equipment if you do not have free access and want to record on videotape
- time of team to observe users (conduct the test)
- cost of paying participants or gifts for participants
- time to consider what the team saw and heard, identify
problems, recommend solutions to those problems
- time to discuss changes with developers, write up memo of
findings and recommendations
Remember to budget for more than one usability test.
Building usability into a Web site (or any product) is an iterative process. You will find
it more valuable to use your budget to do a few small tests throughout development than to
do just one large test at the end. Each small test might include anywhere from three to 10
users.
If you are not sure why to do several small tests, see Why Should I Do Iterative Usability Testing?
If you need to convince people that usability testing is
worth the cost, see:
The evidence we cite in How Can I
Encourage People in My Organization...?
How to calculate the cost-benefit of usability in How Can I Show That Usability Engineering Saves Money?
Why Should I Do Iterative
Usability Testing?
A few small tests are more valuable than one large test
at the end.
- The sooner you find problems, the less expensive it is to
fix them.
- Finding and fixing problems early means less rework. That
not only saves money, it reduces designers' and developers' frustration.
- You can test branding (Do people realize whose site it
is?), navigation (Can people find what they need?), and organization of the home page
before you have developed all the content or coded the entire site.
- You can test many design issues with paper prototypes and
then test again when you have a working site. See Developing Prototypes.
- You can test one part of the content and learn valuable
lessons to apply to other parts that aren't yet developed.
- Changes are more likely to get made early in the
development process. Cost, time, and human reluctance usually lead to ignoring problems
that are found if you test only at the end.
- Testing once isn't enough to be sure you have a usable
site. Use iterative testing to see whether the way you fixed an earlier problem really
works for users.
- You can use iterative usability testing to show how
the benefits of usability engineering greatly outweigh the costs. See How Can I Show That Usability Engineering Saves Money?
How Can I Show That
Usability Engineering Saves Money?
You can use usability testing to show that the benefits
of usability engineering outweigh the costs.
This method was first published by Clare-Marie Karat of
IBM who used it to show a 100-fold return on investment for a particular software product.
In that case, spending $60,000 on usability engineering throughout development resulted in
savings of $6,000,000 in the first year alone.
The results from this technique are especially convincing
if the same organization pays both the development costs of the Web site and the salaries
of the people who use the site. But it should also be convincing to organizations that
really care about how problems on their site cost their external users time, money, and
frustration.
The types of problems that you might find costing time
(and therefore money) are misleading navigational cues, poorly designed pathways, pages
that are so dense they take a long time to use, etc.
Here is how you can use usability testing to show how
benefits outweigh costs:
1. Do a usability test on an early version of the Web
site (or other product) — this could be the old site or one done without involvement
of usability specialists.
- Use actual users doing relevant tasks.
- Measure time to complete tasks.
2. Identify and fix problems. (Improve the entire site
not just the test tasks even though you will be using the test tasks to show the
benefits.)
3. Do a usability test on the new version of the site.
- Have users who match the demographics of the first set of
users do the same tasks you used in the first test.
- Measure time to complete the same tasks.
4. Calculate the improvement in average time to complete
each task.
- You can do the next steps for each task separately, for
just one major task, or for all the tasks together.
5. Multiply the time saved by the number of people who
are likely to do that task in a given time period (say, each day).
- If users are likely to do a task several times a day, you
can also multiply by that number.
- If you have noted the time saved in seconds or minutes,
convert it to hours because you will want to work in hours in the next step.
6. Identify the average hourly salary of the users who do
that task.
7. Convert time to dollars by multiplying time saved (in
hours) by users' salary (per hour).
8. Find the one-year savings by multiplying your previous
figure by the number of days in the year that users are likely to do the task.
- If this is a work task, use the number of days in the
organization's working year.
- You now have the total annual savings of your usability
changes — all due to time saved by fixing the product so users can do tasks more
quickly.
9. Compare the amount saved to the cost of usability
activities.
• For More Information:
Karat, C.-M. Business case approach to cost
justification. In Cost-Justifying Usability, Edited by R. G. Bias and D. J. Mayhew,
Boston: Academic Press, 1994, 45-70.
• Links to Related Articles:
To practice this type of calculation, try the exercise at
http://www.weinschenk.com/tools/roi.asp
How Can I Encourage People in
My Organization to Conduct Usability Engineering and Testing?
If you're trying to persuade the people in your
organization to use usability engineering to design your Web site:
- Quote these statistics:
• Research by User Interface Engineering, Inc.,
shows that people cannot find the information they seek on a Web site about 60% of the
time.
• According to Elizabeth Millard, "The best
sites we've found are usable only 42 percent of the time, and none that we have studied
are usable a majority of the time...."
• Studies by Forrester Research estimate that approximately 50% of potential sales
are lost from a site as users can't find data and that 40% of users do not return to a
site when their first visit is a negative experience.
• A study by Zona Research found that 62% of Web shoppers have given up looking for
the item they wanted to buy online.
- Let them observe a usability test or show them video
footage. Observation of user behavior is very persuasive. The user perspective is just
about impossible for Web site production teams and content developers to see without
talking to or observing actual users.
- Remind them that usability testing doesn't have to be
expensive. Big problems in the design are obvious after just a few user tests. Jakob
Neilsen says, "You sit somebody down in front of the screen and see immediately if
they click on the right button or the wrong one. As soon as you see three people make the
same mistake, you're better off just fixing it."
• Links to Related Sites
Failure
of Corporate Websites, Jakob Nielsen, Alertbox,
http://www.useit.com/alertbox/981018.html
Hard-to-use
Sites Will Fail, Jakob Nielsen, in The Irish Times on the Web,
http://www.ireland.com/newspaper/computimes/
2000/0110/compu1.htm
Usability as Barrier to Entry,
Jakob Nielsen, Alertbox, http://www.useit.com/alertbox/991128.html
Does Your Site Work? Ask
a Usability Guru, David Pescovitz, in The Standard
http://www.thestandard.com/article/0,1902,23498,00.html
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