Transcript Web Design for Usability

CS101 Introduction to Computing
Lecture 25
Web Design for Usability
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During the last lecture …
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We looked at the role of heuristics in
architectural (or high-level) design
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We also became familiar with a few popular
design heuristics
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Heuristic
Rule of thumb learned through trial & error
Common sense lesson drawn from experience
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Caution!
Caution!
Heuristics don’t always
lead to the best results
At times they even lead to the
wrong ones, but mostly to
results that are good-enough
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Given many parts of a system to be designed/built,
do the
hard part
1st
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Today’s Goal:
Web Design for Usability
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To become able to appreciate the role of
usability in Web design
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To become able to identify some of the
factors affecting the usability of a Web page
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When I look at a Web page it should be
self-evident, obvious, self-explanatory
I should be able to ‘get it’ - what it is &
how to use it - without expending
any effort thinking about it
excerpt from Steve Krug’s book Don’t Make Me Think
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don’t make me think!
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Usability!
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What’s a Good Site?
• The one that achieves the result that it was
designed for
• Generally, that result can only be achieved by
giving the user what s/he wants, as quickly as
possible, without her/him expending much effort
• One definition of usability: Let the user have
what s/he wants, quickly, without much effort
• “Quickly” is important!
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speed!
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Users don't read; they scan
Users don't make optimal choices;
they look for the first good-enough
solution
Users don't figure out how things
work; they muddle through
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think roadside billboard
rather than
Dewan-e-Ghalib
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Design is Important!
• 62% of shoppers gave up looking for the item
they wanted to buy online (Zona Research)
• 40% visitors don’t return to a site if their first
visit was a -ive experience (Forrester Research)
• 83% of users have left sites in frustration due to
poor navigation, slowness (NetSmart Research)
• Simple designs have greater impact: they can
be understood immediately! (Mullet/Sano) 15
Simplify, simplify,
simplify!
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Designs should be
consistent &
predictable
(unified)
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Elements of Website Design
1. Navigation scheme
2. Layout of information
3. Overall look and feel
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Website Navigation
• The interface/controls that a Website
provides to the user for accessing
various parts of the Website
• It probably is the most important aspect
of the design of a Website
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A Few Navigation Design Heuristics
1. Put the main navigation on the left of the page
2. It should be ‘invisible’ until it is wanted
3. It should require an economy of action & time
4. It should remain consistent
5. Use text for navigation labels. If you must use
icons, put a description underneath each icon
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Navigation Design Heuristics (contd.)
6. Labels should be clear, understandable
7. Labels should be legible
8. Do not play with standard browser buttons &
features
9. Provide search capability
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- click
navigation
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Now, let’s take a look at
a few good designs …
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A good solution
to a problem
somehow looks
nice & elegant
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Good designs
assist the user
in recovering
from errors
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Assisting the User Recover from Errors
• Location, post code mismatch
• Credit card number errors
• Phone numbers
• Spelling errors
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A few constructive
recommendations
Let’s look at a few Web sites and see how
we can improve their usability
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Enter
Dragon’s Lair
All rights reserved, 2002.
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WWW
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LOADING …
RESTART
SKIP
Click here to go to the main page directly
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A few more Web
design heuristics
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1. Designing
(arranging)
Display
Elements
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Making Display Elements Legible
1. Elements must be large enough to
be processed visually
2. Elements must contrast sufficiently
with their backgrounds
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Making Display Elements Legible
3. Related elements should be visually
grouped through the use of space,
color, or graphical boundaries
4. The relative levels of importance
among elements in a display should
be revealed graphically
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2. Ensuring
Text is
Readable
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1. Use sans serif (e.g. Arial, Helvetica,
Verdana) typefaces for display on screen
2. Display type intended for continuous
reading at 10 to 14 points
3. Avoid the overuse of bold and italics
4. Avoid setting type in all caps
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5. Arrange type intended for extended
reading flush left, ragged right
6. Avoid lines of type shorter than 40
characters and longer than 60 characters
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7. Mark the boundaries between paragraphs
with blank lines rather than indentation
8. Use headings and subheadings to visually
reveal the relationships among text
elements they label – paragraphs after
paragraphs of text do not work that well on
the Web
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3. Using
Pictures &
Illustrations
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Avoid using
pictures that
are strictly
decorative
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4. Using
Motion
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1. Use motion to attract the viewer’s
attention
2. Avoid the use of motion for “cosmetic”
purposes
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Success is defined by
the user, not the builder
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In Today’s Lecture
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We looked at the role of usability in Web site
design
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We identified some of the factors affecting
the usability of a Web page
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Reading Assignment
www.useit.com
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Next Lecture:
Computer Networks
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We will become able to appreciate the role of
networks in computing
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We will familiarize ourselves with various
networking topologies and protocols
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