Website usability

1
Website usability

• Surprising findings from the research

Marianne W. Zawitz Sept. 25 - 27, 2000
Bureau of Justice Statistics
2
What is usability?

• The measure of the quality of the user
  experience when interacting with something --
  whether a traditional software application, or
  any other device the user can operate in some way
  or another.

Jakob Nielsen Devhead, www.zdnet.com, 9/29/98
Bureau of Justice Statistics
3
Usability is measured by

• Ease of learning
• Efficiency of use
• Memorability
• Error frequency and severity
• Subjective satisfaction

Bureau of Justice Statistics
4
The usability profession

• From cognitive psychology
• Focused on Human Computer Interface (HCI)
• Initial work was testing software interfaces

Bureau of Justice Statistics
5
What is usability testing?

• Researchers devise a series of tasks to
  accomplish based on the objectives of the
  software
• Subjects asked to perform the tasks in a
  laboratory setting
• Usually work with small number of subjects (6-8)

Bureau of Justice Statistics
6
Usability techniques have been applied to the web

• Designing Web Usability, Jakob Nielsen, 2000
• Web Site usability A Designers Guide, Spool, et
  al. 1997
• Keith Instones Usableweb (http//usableweb.com/)
• many more in handout

Bureau of Justice Statistics
7
Benefits of Usable Sites

• Reach a broader audience
• Facilitate move away from paper dissemination
• Users find the information they need
• Users dont waste time or make errors
• Users are impressed with the sponsor
• Users return to the site and recommend it to
  others

Bureau of Justice Statistics
8
Need for speed

• According to the Graphic Visualization and
  Usability Centers 10 Survey (April 1999)
• Two thirds of respondents connected to the
  Internet at 56K or less

Bureau of Justice Statistics
9
When asked What do you find to be the biggest
problems using the Web?

• Slow ads were the most frequently reported
  problem
• Speed came in a close second

Bureau of Justice Statistics
10
What is the single most important issue facing
the Internet?

• Speed was second only to privacy

Bureau of Justice Statistics
11
the Bandwidth problem will has not been solved
in the last three years nor will it be solved
during the next three years. Not until 2003 will
high-end users have sufficient bandwidth for
acceptable Web response times. Low end users
will have to wait until about 2008.
Jakob Nielsen, May 1999
Bureau of Justice Statistics
12
Tips for speeding up your site

• Measure how long it will take for a page and its
  dependencies to download
• Avoid unnecessary graphics particularly image
  maps
• Reduce the number of colors in the graphics you
  do use
• Use width and height specifications for all
  images

Bureau of Justice Statistics
13
User behavior

• Reading
• Scrolling
• Animation

Bureau of Justice Statistics
14
Reading on the web is different than reading a
document

• Users scan content
• In a study by Nielsen and Morkes
• 79 of users tested always scanned new pages
• 16 read word-by-word
• On screen reading is 25 slower than on paper

Bureau of Justice Statistics
15
Legibility

• Text and background must have high contrast
• Avoid all caps
• Avoid text that is too small

Bureau of Justice Statistics
16
Terminology

• Users have difficulty with technical or domain
  specific terms
• Users are unsure of where categories may lead
  especially if they are cutsey
• Users hate marketese

Bureau of Justice Statistics
17
Writing for the web involves

• Chunking
• Inverted pyramid style with the conclusions
  first
• Meaningful subheadings and keywords
• Bulleted lists
• One idea per paragraph
• Half the word count than conventional writing

Bureau of Justice Statistics
18
Users are willing to scroll

• Need a reason to go down the page
• The fold is not a constant
• Users were just as likely to have their first
  click below the fold as above the fold

Bureau of Justice Statistics
19
Animation is uniformly annoying

• Users will ignore animated objects thinking they
  are advertisements
• Many users will scroll down to avoid animations
• Some users turn off animation in their browsers

Bureau of Justice Statistics
20
Organization

• Users have no patience with disorganized sites
• In the Breadth Vs. Depth Battle, users prefer
  breadth (few clicks to content)

Bureau of Justice Statistics
21
Navigation

• Users dont have a perceived mental model like
  they do with software
• Shell structures with generic navigation do not
  work
• Links with short titles do not work
• Navigation needs to fit with content

Bureau of Justice Statistics
22
Users need to know where they are

• Users tend to go forward
• When users navigate beyond four or five pages
  they forget how to get back
• Using the same navigation on every page can
  confuse people
• Differences in navigation based on context are
  helpful
• Indications of where they are help

Bureau of Justice Statistics
23
Navigation bars

• Users do better with navigation bars at the top
  or bottom rather than the side
• Duplicated links on the left and bottom confused
  people
• Clues that you were on a particular page on the
  nav bar were very helpful
• Except for the home page, no more than 20 of
  the page should be navigation

Bureau of Justice Statistics
24
Crumbs are a very useful device to show users
where they are

• Homegt Products gtPublicationsgt Order

Bureau of Justice Statistics
25
Links for navigation

• The number of links is negatively correlated
  with success in finding information
• Users try to rule out links that are not going
  the right place
• Users cannot remember more than 7 links

Bureau of Justice Statistics
26
Other navigation devices

• Users like Tables of Contents with sub-items to
  take them directly to content
• A site map is helpful but not as good as a Table
  of Contents
• FAQs frustrate users seeking specific information

Bureau of Justice Statistics
27
Searching

• About one third of the users in UIEs study
  always went to the search facility
• Users were often confused about what is covered
  by the search
• Search results are often very confusing or lack
  information to tell the user what the link was

Bureau of Justice Statistics
28
Links

• Graphics
• Color
• Text
• New title option
• Embedded

Bureau of Justice Statistics
29
Graphics do not work well as links

• No indication that they are links
• Visited links do not change color
• If they are buttons they may not be big enough
  for the user to determine they are links

Bureau of Justice Statistics
30
Users get confused when link colors are not
standard

• Unvisited links should be blue
• Visited links should be reddish or purple
• Using standard colors means users dont have to
  learn anything new

Bureau of Justice Statistics
31
Users want to know what they are going to get
when they link

• 7 - 11 word descriptions are most useful
• Anchors should be 3 - 4 words
• Words must be informative to be useful
• Use words users know avoid ambiguity

Bureau of Justice Statistics
32
Embedded links are harder to follow than separate
links

• Due to the way users scan the page
• Use embedded links for contextual information
  rather than for navigation to information
• Dont underline nonlink material

Bureau of Justice Statistics
33
Graphics

• Do not help or hurt unless they slow you down
• Many users will not wait for a graphic unless
  they think it has content they want
• Always provide ALT tags for users who are
  browsing without graphics on or who use assistive
  devices

Bureau of Justice Statistics
34
Reliability of information

• Users want too know who is presenting
  information
• Some users prefer to see the date of the last
  update
• Reputation managers are contributing to ensuring
  the reliability of information(eBay, Epinions,
  Google, Go)

Bureau of Justice Statistics
35
Top 10 Mistakes of Web Design

• Frames
• Bleeding-edge technology
• Scrolling text and looping animations
• Complex URLs
• Orphan pages
• Scrolling navigation pages
• Lack of navigation support
• Non-standard link colors
• Outdated information
• Slow download times

Jakob Nielsens Alertbox
36
Top 10 New Mistakes of Web Design

• Breaking or slowing down the back button
• Opening new browser windows
• Non-standard use of GUI widgets
• Lack of biographies
• Lack of archives
• Moving pages to new URLs
• Headlines that make no sense out of context
• Jumping at the latest Internet buzzword
• Slow server response times
• Anything that looks like advertising

Jakob Nielsens Alertbox
37
Accessibility must also be considered a usability
issue

• Many users --
• have disabilities
• are from foreign countries
• connect on slow modems or use older equipment and
  software

Bureau of Justice Statistics
38
Quick tips for accessible sites

• Images and animations - Use ALT tag
• Image maps - Use client side image maps
• Multimedia - Provide text descriptions of all
  audio and video
• Hypertext links - Use text that makes sense -
  avoid click here
• Page organization - Use headings and lists and
  consistent structure

Bureau of Justice Statistics
39
More quick tips for accessible sites

• Graphs charts - provide a text description
• Scripts, applets plugins - Provide alternatives
• Frames - Use Noframes and meaningful titles
• Tables - Make line-by-line reading sensible
• Check your work - validate

Bureau of Justice Statistics
40
Accessibility resources

• W3C Web Content Accessibility Guidelines
• Unified Web Site Accessibility Guidelines - TRACE
  Center
• CASTs Bobby
• Lynx viewer

Bureau of Justice Statistics