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CS101 Introduction to Computing

Lecture 25Web Design for Usability

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During the last lecture …

• We looked at the role of heuristics in architectural (or high-level) design

• 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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CautionCaution!!CautionCaution!! 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 1st1st

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Today’s Goal:Web Design for Usability

• To become able to appreciate the role of usability in Web design

• 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 beself-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)

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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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11- click- click

navigationnavigation??

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Now, let’s take a look ata 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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WW WW WW

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SKIPRESTART

LOADING …

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 tobe 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, notnot the builder

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In Today’s Lecture

• We looked at the role of usability in Web site design

• 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

• We will become able to appreciate the role of networks in computing

• We will familiarize ourselves with various networking topologies and protocols