Usability in Website Design
There is no single approach to developing a usable website. The
guidelines in this section deal with overall site structure and design.
They are based on studies of what users like and
dislike about commercial websites, and what features help users
accomplish their tasks with the least effort and errors.
Key Usability "DOs"
User tests have identified some characteristics that particularly
help users:
- To the extent possible, pages at a single website should
share a common look-and-feel. Users become annoyed when
they can find a particular feature - such as "search" or "help" -
on some portions of the site, but not others. It's even worse when
links, menus, or button labels change dramatically from one page
to the next. See Elements Shared by All
Site Pages for more information.
- Starting with the homepage, each webpage should include real
content, not just promises of other materials to come (see
Site Organization). This page, for
example, actually begins describing usability rather than just listing
sections that are available on other pages.
- Webpages should honor the user's browser settings, rather
than overriding them. Users may have particular reasons for employing
particular font sizes or link colors, and will not appreciate pages
that hardcode values to defeat those settings (see
Page Design for examples).
- Whenever possible, webpages should support browser resizing.
Given the wide range of screen sizes and resolutions available, no
particular size can be assumed; in addition, users may have an important
reason for resizing (e.g., to capture a screendump of particular
dimensions). Pages should be written so that at least the primary
textual content can expand or contract as the window is resized
(see Page Size).
Key Usability "DON'Ts"
Usability studies have also indicated that a few general website features
are guaranteed to discourage users. All of them are easily avoidable:
- Don't use frames. Users object vigorously to frames, for
a number of reasons:
- Printing doesn't "work properly" from the user's standpoint - users
expect to print exactly what they see, not just a portion of it.
- Navigation is just plain clumsier with frames. This is particularly
true when the right mouse button is needed - most users never employ that
mouse button, period.
- The back button doesn't "work properly" in many browsers, in the
sense that it may not take the user where he/she expects to go.
- Most browsers are unable to bookmark individual pages within the site
in the presence of frames.
- Users can't cut-and-paste URLs to send to other people - or to embed
them as cross-references from their own Web pages.
- In some implementations, links leading to other Websites get messed
up as well. For example, after following the link to NSF's NEES Website,
the browser may still show your site as the URL!
- In general, don't pop up windows without the user's permission.
Instead, links should just transfer the window to the
new URL. This allows the user to maintain control over how the screen
is used. Obvious exceptions are:
- Help facilities, since the user needs to see not just the help
description but also what's being described.
- Video and audio clips, which require special players.
If you think an additional window is necessary, let the user know
as part of the link; e.g., "Visualization of Sensor Data (in new
window)".
- Don't have a "banner page", even if it transitions automatically
to your homepage. Users appear to dislike these because they are "too
slick" and imply a marketing pitch. Users particularly object when the
banner page includes animation or sound.
- Don't say "welcome" on your webpages. Users already know you
want them to visit your site - why be "cute" about it?
- Don't bother including a copyright notice, since it is no longer
needed to establish ownership to Web materials. If you feel strongly
about having this, it should appear on the homepage only, not on every
page.