Jakob Nielsen's
Alertbox, August 22, 1999:
Do Interface Standards Stifle Design Creativity?
No design standard can ever specify a complete user interface. Thus, by
definition, much design work remains, even if the designer is committed
to complying with the appropriate standards.
Often, the most important design elements are
those that cannot be specified by a standard, since the standard cannot
know the specifics of the individual domain addressed by the design.
For example, I was recently involved in the design of an e-commerce
site. The draft home page had three ways of getting to the products: search
and two navigation schemes, both of which were presented as simple lists
of choices. One navigation scheme was structured according to the way most users
think about the domain; the other scheme was structured
according to the way many of the manufacturer's own staff thought about their product
lines. Results from usability testing:
- success rate of 80% when people used
the navigation scheme structured according to most users'
mental model
- success rate of 9% when people used
the navigation scheme structured according to the
company's internal thinking
Conclusion: the second navigation scheme was dropped from the design, even
though this pained some of the project members. The second scheme had its
advantages for those people who used it correctly,
but it led most users into trouble, so it did more harm than
good.
I mention this result for two reasons: First, even though both navigation designs
looked identical and
followed the same interface standard in terms of appearance, layout, and
interaction techniques, their usability was drastically different. The first
design was almost nine times better than the second. This difference sums
to big dollars for an e-commerce site that will sell nothing unless
users can find the products. The difference in usability was not due to
differences in surface design but to differences in deep
design: finding
out how to best match a Web design to the users' needs and how to best
structure the information architecture. Thus, even when sticking to a
design standard, there was plenty to do for the site designers. A bad
designer would have used the bad navigation scheme on the home page
and never tested it.
Second, the result also shows that great usability is not guaranteed even
when following a detailed design standard to the letter. A standard
ensures that your users can understand the individual interface
elements in your
design and that they know where to look for what features. It does not
ensure that users will know how to combine the interface features or that the
system will have the features users needs.
Eric Davis, an
Information Architect with Resource Marketing, recently reported on
a usability test of shopping cart terminology.
The draft design featured the term "Shopping Sled" since
the site (selling winter sports products) had a desire to stand out
and avoid standard terminology. Result: "50% of users did not understand
The Sled concept. The other 50% said that
they figured out what it meant because it was in the same location as a cart
would be. They knew that you had to add to something, and the only
something that made any kind of sense was the Sled." Lesson: Do not try to be
smart and use new terms when we have good words available that users already
know.
Of course, there is no guarantee that a site that uses the term "shopping
cart" will have a shopping interface that is easy to use. All that is
ensured is that users will understand the term when they see it
used as a link around the site.
But that's a usability benefit well worth taking.
Jakob's Law of the Web User Experience: Users spend most
of their time on other sites. Thus, anything that is a
convention and used on the majority of other sites will be burned into
the users' brains and you can only deviate from it on pain of major
usability problems.
Since the dawn of time (1984), we have known that consistency is one of the
strongest contributors to usability. The Macintosh was based on a detailed
book of Apple Human Interface Guidelines that were followed by almost all
applications. One of the main benefits of the Mac (and later Windows) over
earlier systems was the resulting consistency that made it possible for users
to use software right out of the box. For example, people knew that you
could move stuff around by a sequence of (1) select-object, (2) Cut-command,
(3) scroll-to-new-location, (4) click-on-insertion-spot, (5) Paste-command. Always the
same sequence. And the Cut and Paste commands were always in the Edit menu
and were always abbreviated Command-X and Command-V. No real reason people
should associate the letter V with insertion or pasting, but since it was
always the same, it worked.
Despite the strong consistency in all Mac software do you think Excel
looks like MacWrite? Or that there was no design creativity involved in
making MORE (a popular outliner)?
It's clearly not the case that all GUI software is the same even though
most software has pretty strong compliance with the platform
design standards these days.
Similarly for the Web: following design standards simply ensures that users
know what you are talking about. It's like using standard English words rather than
your own vocabulary when writing. You are still the one who decides what
story to tell and how to put the design elements together.
Rules for Design Standards
To be successful, an interface design standard must:
- be well-illustrated with examples since designers go
by the examples much more than body text
- make sure that the examples fully comply with the standard in
all aspects and not just the one they are intended to illustrate
(designers may pick up more than one hint from a given example)
- have extensive and comprehensive checklists as much
as possible (designers prefer to scan down a list instead of having to
read text) - for example, a list of all elements that must be on every page
or a list of preferred terminology
- have a standards expert available both to review new designs in a formal
standards inspections and for more informal consultations
whenever designers are in doubt about the correct interpretation of the
standard (if there is no easy place to turn with questions, then each
designer will make up his or her own answer - guaranteed to be different
in each case)
- be supported by an active evangelism program. It is
not enough to wait to be consulted: you must actively seek out projects
and visit them to tell them about the standard and to (gently) comment on
their designs and how to correct the inevitable deviations
- be a living document under the control of a standards
manager who updates the standard as new issues emerge
- either comply with the most popular other design
standards or contain explicit statements highlighting the
differences to these other standards
- be supported by development tools and templates that make it
easier to comply with the standard than to implement
a non-standard design
- have a good index (if printed) or a good search supplemented with
hypertext links to related rules (if online)
Evangelism outreach is especially important for intranet
standards since every department will have an inclination to
ignore mandates from headquarters. They usually do so with the
excuse that "we are different and the folks at HQ don't know our
situation." True, but everybody is special
so the total system will be utter chaos if people are allowed to
diverge because of special circumstances. Usually, the greater good
is indeed greater, and overall usability is increased by consistency.
There can be a few cases where circumstances are so special that
an inconsistency should be tolerated, but deviations must be limited
to cases with a very, very good reason (most good reasons are not good
enough).
Finally, realize that a standard has its own usability concerns. This is
true whether the standard is implemented as an interactive website
with hypertext links or whether it is a traditional printed document.
Therefore a
proposed design standard should be tested with designers to ensure that they
can use it.
