1 CS101 Introduction to Computing Lecture 25 Web Design for Usability

2 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

3 Heuristic Rule of thumb learned through trial & error Common sense lesson drawn from experience

4 Caution ! Caution ! 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

5 1st Given many parts of a system to be designed/built, do the hard part 1st

6 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

7 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

8 don’t make me think!

9 Usability!

10 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!

11 speed !

12 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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14 think roadside billboard rather than Dewan-e-Ghalib

15 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)

16 Simplify, simplify, simplify !

17 Designs should be consistent & predictable (unified)

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20 Elements of Website Design 1.Navigation scheme 2.Layout of information 3.Overall look and feel

21 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

22 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

23 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

click navigation ?

25 Now, let’s take a look at a few good designs …

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27 A good solution to a problem somehow looks nice & elegant

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32 Good designs assist the user in recovering from errors

33 Assisting the User Recover from Errors Location, post code mismatch Credit card number errors Phone numbers Spelling errors

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35 A few constructive recommendations Let’s look at a few Web sites and see how we can improve their usability

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37 Enter Dragon’s Lair All rights reserved, 2002.

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40 W W WW W WW W WW W W

41 SKIPRESTART LOADING … Click here to go to the main page directly

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43 A few more Web design heuristics

44 1. Designing (arranging) Display Elements

45 Making Display Elements Legible 1.Elements must be large enough to be processed visually 2.Elements must contrast sufficiently with their backgrounds

46 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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48 2. Ensuring Text is Readable

49 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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52 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

53 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

54 3. Using Pictures & Illustrations

55 Avoid using pictures that are strictly decorative

56 4. Using Motion

57 1.Use motion to attract the viewer’s attention 2.Avoid the use of motion for “cosmetic” purposes

58 not Success is defined by the user, not the builder

59 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

60 Reading Assignment

61 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