Good usability is critical to the success of a website. Usability
evaluation has traditionally been a slow, labor-intensive process
which makes it difficult to apply to websites. The dynamic nature of
the Web poses problems for usability evaluation. Development times are
rapid and changes to websites occur frequently, often without a chance
to re-evaluate the entire site. Advances in web-based user interfaces
change user expectations. Finally, the potential audience for a
website may be geographically dispersed and encompass a wide range of
The challenge then is to determine how best to provide automated
support to the usability engineer. Automated techniques cannot
entirely supplant manual testing; the intuition of a good usability
engineer is still vital. However, automated techniques can enhance
traditional approaches and provide additional information to the
developer as well.
The objective of the NIST Web Metrics Testbed is to explore the
feasibility of a range of tools and techniques that support rapid,
remote, and automated testing and evaluation of website
usability. The prototypes are used to support the usability
engineering research of the Visualization and Usability
Group (VUG). As part of the
Information Access Division of the Information Technology Laboratory
at the National Institute of Standards
and Technology, VUG encourages industry to use and/or
commercialize its ideas.
The NIST Web Metrics testbed was undertaken in 1997 to explore
solutions to the problems described above. We released version 1
(consisting of simpler versions of WebSAT, WebCAT, and WebVIP) in June
of 1998. Since that time, we have enhanced the original software and
added FLUD and VisVIP.
We are now (October 2002) releasing a new version of Web Metrics with
even more improvements. Please take a look at our What's New page for the details.
Prototype Tools from the Web Metrics Testbed--
Static Analyzer Tool (WebSAT) checks the HTML of web pages against
usability guidelines, either its own, or a set of IEEE Std 2001-1999
guidelines. It can check individual pages or an entire website. |
Category Analysis Tool (WebCAT) lets the usability engineer quickly
construct and conduct a simple category analysis across the web. It is a
variation upon traditional card sorting techniques. The usability engineer
establishes a set of categories and a number of items which are to be
assigned by test subjects to those categories. The engineer can then
compare the actual assignments with the intended usage to make sure that
the categories match users' intuitions. |
Variable Instrumenter Program (WebVIP) lets the usability engineer
rapidly instrument a website so as to capture a log of user behavior on
the site. Once the site is instrumented, test subjects are asked to
complete tasks typical of those for which the site was designed. Their
interactions (such as navigating among pages and manipulating buttons and
checkboxes) are captured in a log file for later analysis. Note that even
remote users can be tested. |
for Logging Usability Data (FLUD) is a file format and an associated
parser for representation of the behavior of website users. The captured
log data can be valuable for analyzing and improving the usability of
web-based applications. This log data is quite complex and therefore a
common file format is needed to allow various software components (such as
recorders, parsers, analyzers, and visualizers) to exchange information.
||The FLUDViz tool lets the usability
engineer (UE) visualize and analyze a single usability session. The
x-axis is used for time, and the y-axis for the types of behavior.
The UE can zoom and pan in the time dimension by manipulating a time
slider at the bottom of the display. The UE can also filter activity
type in the Y dimension through the control menu.
tool lets the usability engineer visualize (in 3D graphics) and
analyze the navigational paths of website users as captured in a FLUD
file. VisVIP automatically lays out a 2D graph of the website, and then
overlays the paths of selected subjects to show which pages were visited.
A vertical bar indicates how much time users spent at the various pages.
The TreeDec tool supports the
representation of a website as a single
logical tree. It automatically adds links (such as so-called
"breadcrumbs") to each page of the website to allow easy
navigation to nearby nodes of the tree.