User Interface Design for the Web

Lawrence Najjarlnajjar@viant.com

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Outline

• Why usability is important

• Challenges for designing Web-based user interfaces

• Web user interface design process

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Why Usability is Important

• Biggest problem with Web is download time1 • Second biggest reason people don’t buy from Web site is

navigation difficulties2 • 28% of Web shoppers surveyed had trouble finding the

product they wanted3 • 83% of Web shoppers surveyed left a site due to bad

performance, especially poor navigation and slow downloads4

• 62% of Web shoppers surveyed gave up looking for a product online3

• Dissatisfied customers tell about 10 others5

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Why Usability is Important (continued)

• If usability improved, sales can improve – IBM sales increased 400% after site redesign6

– Digital Equipment Corporation found 80% increase in revenue7

• One study8 estimated that improving the customer experience increases conversion rate by 40% and increases order size by 10%.

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Challenges for Designing Web-based User Interfaces

• Short download times

• Limited interaction options (ex. no drag-and-drop)

• Broad user population

• Impatient users

• Many application choices

• Diverse interaction hardware and software

• Multiple languages

• Disabled users

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Web User Interface Design Process

1. Define users

2. Define functional requirements

3. Write use cases

4. Develop site diagram

5. Build interactive wireframe mockup

6. Test usability

7. Write functional design specifications

8. Perform acceptance test

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1. Define Users

• Develop user profile

• Perform experience architecture

• Create personas and scenarios

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User Profile

Gender Generally male

Age 30 to 50 years old

Education High school graduate

Income $25,000 to $45,000 per year

Location Facility manager office in office building

Computer experience

Moderate. Facility manager uses computer for e-mail and researching products on the Web

Computer IBM-compatible personal computer

Web connection Slow connections (56K modem)

Objectives Want to save time, reduce costs of running facility, monitor security, and control specific equipment as needed.

Facility Managers

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Experience Architecture

Intent

Audience

Context

Learn about products

Solve problems

Get entertainedHome

Work

Tech

exp

ert

Tech

nov

ice

Gadge

t lo

ver

10

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2. Define Functional Requirements

• Identify functional requirements– Ask client

– Ask users – focus groups, interviews, contextual inquiry, questionnaires

• Prioritize functional requirements

• Select functional requirements

• Get client approval

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Functional Requirements

Function Description PriorityRegister Enter registration and

personalization informationLow

Search Find product High

Browse Browse catalog for product High

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3. Write Use Cases

• Identify use cases

• Prioritize use cases

• Scope use cases

• Select use cases

• Get client approval

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Use Cases

Use CaseTask Flow Description User

PreferenceDifferentiation from Competitors

Technical Difficulty

Show confirmation

Provide confirmation when user adds, edits, or erases registration

Medium Low Low

Remove confirmation

Take the confirmation off the page

Low Low Low

Change registration

Edit user’s reg. information

Medium Medium Low

Remove registration

Erase user’s registration

Low High Low

Function Description PriorityRegister Enter registration and personalization information Low

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4. Develop Site Diagram

• Identify sections and subsections

• Name sections

• Iterate with client

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Site Diagram

Home Page

Home Page

Widgets

Analog

Digital

Customized

Gadgets

Handheld

RemoteControlled

Supersonic

Geegaws

Childrens'

Search Browse About Us PrivacyTerms &Condition

s

Global Navigation

ContactUs

GeegawSelector Tool

General

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5. Build Interactive Wireframe Mockup

• Show how functions may work9

• Don’t show graphics

• Don’t use raw HTML

• Don’t connect to databases or other tools

• Iterate with client

• Make changes quickly and cheaply

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Interactive Wireframe Mockup

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6. Test Usability

• Add graphics to several typical task pathways

• Recruit five representative users

• Ask users to try to perform typical tasks

• Record problems

• Ask participants to complete questionnaires

• Fix interactive wireframe mockup

• Repeat

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Usability Test

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7. Write Functional Design Specifications

• Capture image of functional design of each page

• List each control

• Describe how each control works

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Functional Design Specifications

Global buttons – top navigation bar GE Home - links to the GE Home page at http://www.ge.com Customer Center Home - links to the Power Systems customer center at

http://schexnweb.sch.ge.com/cgi-bin/xnetmainmenu.exe Sales and Service Home - links to the GE Power Systems Sales and Service home page

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8. Perform User Acceptance Test

• Use actual pre-launch site

• Ask representative users to perform typical tasks

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Conclusion

• Web usability is important• A user interface design methodology can help

improve usability• The real world is different from the academic

world

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References1 Graphics, Visualization, and Usability Center (1998). GVU’s 9th WWW User Survey. Atlanta: Georgia

Institute of Technology, College of Computing, Graphics, Visualization, and Usability Center. Available: http://www.gvu.gatech.edu/user_surveys/survey-1998-04

2 Kadison, M. L., Weisman, D. E., Modahl, M., Lieu, K. C., and Levin, K. (1998, April). On-line Research Strategies: The Look to Buy Imperative. Forrester Report, 1(1). Available: http://www. forrester.com

3 Seminerio, M. (1998, September 10). Study: One In Three Experienced Surfers Find Online Shopping Difficult. Inter@ctive Week. Available: http://www.zdnet.com/intweek/quickpoll/981007/ 981007b.html

4 Thompson, M. J. (1999, August 9). How to frustrate Web surfers. Industry Standard [On-line]. Available: http://www.thestandard.com/metrics/display/0,1283,956,00.html

5 Albrecht, K. & Zembre, R. E. (1985). Service America. New York: Warner.6 Tedeschi, B. (1999, August 30). Good Web site design can lead to healthy sales. New York Times e-

commerce report [On-line]. Available: http://www.nytimes.com/library/tech/99/08/cyber/commerce/30commerce.html

7 Wixon, D., & Jones, S. (1992). Usability for fun and profit: A case study of the design of DEC RALLY version 2. Internal report, Digital Equipment Corporation. Cited in Karat, C., A business case approach to usability cost justification. In Bias, R. G., & Mayhew, D. J. (1994). Cost-justifying usability. San Diego: Academic Press.

8 Creative Good (2000, June 12). The dotcom survival guide. Creative Good [On-line]. Available: http://www.creativegood.com/survival/

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References (continued)9 Najjar, L. J. (2000). Conceptual User Interface: A new tool for designing e-commerce user

interfaces. Internetworking, 3.3 [On-line]. Available: http://www.internettg.org/newsletter/dec00/article_cui.html

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Additional Readings

• Najjar, L. J. (1990). Using color effectively (TR 52.0018). Atlanta, GA: IBM Corporation. Available: http://mime1.gtri.gatech.edu/mime/papers/colorTR.html

• Najjar, L. J. (1999, June). Beyond Web usability. Internetworking, 2.2 [On-line]. Available: http://www.InternetTG.org/newsletter/jun99/beyond_web_usability.html

• Najjar, L. J. (in press). E-commerce user interface design for the Web. In Proceedings of 9th International Conference on Human-Computer Interaction. Mahwah, NJ: Lawrence Erlbaum. Available: http://mime1.gtri.gatech.edu/mime/papers/e-commerce%20user%20interface%20design%20for%20the%20Web.html

• Nielsen, J. Useit.com http://www.useit.com

• Nielsen, J. (2000). Designing Web usability. Indianapolis: New Riders.