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Shaw: E-commerce and the digital economy Ch 6: Human factors and e…
Shaw: E-commerce and the digital economy
Ch 6: Human factors and e-commerce
Important points
McCracken & Wolfe 2004: "You are not your user"
Negroponte 1988: designer introspection: designer builds the system according to his or her own taste
HCI = Human-computer interaction
In many cases web design has more usability issues than application design
Common usability problems on the web (Brinck et al 2002)
Navigation disorientation
Human memory limitations
Human perception problems
Database integration
Designers are inexperienced
graphical user interfaces
visual programming languages
interface standards
tools that allow creating of standard system components
published research about usability standards and practices
tools that allow users to critique quick prototypes
users involved better in defining the requirements
planning for incremental improvements, iterative processes
Users are inexperienced
The only effective remedy to reduce problems with inexperienced users is training
Improving the usability of systems
There is no ideal design for a system
There are no universal guidelines for every aspect of an interface
Sites must differ in meaningful ways or the online world will bore the user
Improving the usability of systems
:!: Design principles (Gould et al 1987)
Iterative design (redesign as necessary and try again)
Early focus on users and tasks (to understand them very well)
Empirical measurement (observe actual users doing actual tasks with a candidate design or simulation)
Testing and iteration helps: the benefit-to-cost ratio grows significantly until 5 iterations
The Smith and Mosier guidelines (1986)
Categories
User guidance
Data display
Data transmission
Data entry
Data protection
Sequence control
:!: 5 objectives
Compatibility with other tasks
Flexibility for greater user control
Minimal memory load on the user
Efficiency; minimizing user actions
Consistency
:!!: Shneiderman's 8 golden rules (1998)
Reduce short-term memory load
Support internal locus of control (allowing users to feel they control the computer, not the other way round)
Permit easy reversal of actions
Offer error prevention and simple error handling
Design dialogues to yield closure (allowing people to know their progress and when they're finished)
Offer informative feedback (for every user action)
Enable frequent users to use shortcuts
Strive for consistency (in procedures and terminology)
McCracken and Wolfe's heuristics (2004)
Know the user
Organize content in a meaningful way
Organize the screen in a meaningful way
Build a prototype of key screens, test, redesign
Color theories
Become familiar with basic typography
Use multimedia sparingly
Accessibility, users with disabilities / impairments
Global differences, localization
Build trust by suppression of personal information
Web site accessibility guidelines
The web accessibility initiative (WAI)
Synthesis: how to design
Brinck et al (2002): Pervasive Usability Process
Production
Conceptual design
Launch
Requirements analysis
Mock-ups and prototypes
Maxwell 2002: Maturity model for human-computer interaction (HCI)
Level 2: achieved when devices and sw support the person's role
Level 3: idealized future environment, where people take advantage of embedded and pervasive devices, electronic agents and virtual presence
Level 1: achievement of basic usability
HCI theories, rules and findings
Understanding human reactions to design
(p. 100)
:!: Fitt's law: "the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target"
The most frequently used icons should be larger than the least used icons
Differentiation of icons through colors and shapes, larger icon size
Icons should be larger, rather than smaller
Navigation behavior
Searching
Important
Provide search facilities
Use familiar terms
Creative paths can be effective
Provide multiple paths to important content
Response time
Depth and breadth of a site
Design broad, rather than deep sites
Organize the links meaningfully
Deepen a site only when the delay is short
Visualization of information
McCracken & Wolfe 2004
Alignment
Consistency
Proximity
Contrast
Provide short forms
Provide output that matches user's skills and the tasks
Heuristics: simplification, grouping, consistency
Case, location, density, complexity
Consistency and contrast
Color coding, 3D displays, fisheye displays
Mental models
Do not make assumptions about the web shopper's knowledge or experience
Make instructions very clear and explicit
Build schematic knowledge whenever possible by employing useful analogies
Designing the site
Storyboards and checklists
GOMS and the keystroke model
GOMS = Goals, Operations, Methods and Selection Rules
Keystroke model = estimate the time that each task takes