SWE205 Review
Spring 2014
Why is software unusable?
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Users are no longer trained. Why?
Feature creep
Inherently hard: a problem of communication
Designed inside-out
Give some examples of the 7±2 rule in
a software interface
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Items in a menu
Options in a command line interface
Steps in a process?
What do we do if there are more than 7
options?
– But how do you decide on divisions?
5 criteria for measuring usability
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Time to learn
Speed of performance
Rate of user error
Skill retention
Subjective satisfaction
• List a product where each one is the most
important
• List one way each can be improved
9 golden usability principles
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Consistency
– What if newer is better?
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Shortcuts
– Where? How many?
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Feedback
– Examples
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Closure
Error handling
– Components of a good error message?
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Undo
– What if we can’t undo?
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Customization
Reduce short term memory load
– More knowledge in the world?
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Design for the user
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Explain each one of these on/for Amazon.com
Knowledge
• Declarative vs procedural
– Memorization versus a deeper understanding
• Humans are imprecise; a UI must not require it
• Manifest model:
– Implementation: network protocols
– Mental : files
– Manifest model: local disk
• How does a user know what to do
– Transfer knowledge, seek instructions
Hypertext engineering
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What are images used for?
Animation?
Scrolling? (how to avoid vertical?)
Frames?
What should I do with a link?
Nielsen’s top 10 mistakes. Fixes?
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Bad search
PDFs
Link color after visit
Text blocks
Fixed font size
Un-findable pages
Ads
Violating conventions
Opening new windows
Not answering the user’s questions
How to speed up web interaction?
• Create clear visual hierarchy
• Take advantage of conventions
– Shopping cart, etc.
• Break pages up with borders and colors
• Make what’s clickable obvious
• Minimize noise
• How do we measure speed?
Six elements of persistent navigation
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Site ID
Link home
Search
Sections
Utilities
Current indicators
• On all pages, except?
How to make the UI disappear?
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Defaults should be most likely (or used)
40% versus 20,000 bytes
Indicate status
Don’t use dialog boxes for normal behavior
Don’t ask questions, give choices
Make dangerous choices hard to reach
Elements of a good homepage
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Same as normal webpages, plus:
Teasers
Registration
Deals
Establish credibility and trust
Taglines
Elements of good navigation
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Don’t use multiple windows
Tabbed panes
Toolbars versus menus?
Avoid scrolling and linking
Breadcrumbs
Persistent screen objects
Elements of good data entry
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Knowledge in the world
Use constraints
Design for error
Make software immune from bad data
– Automatic repair
– Ignore invalid characters
– Modeless feedback for missing data
What are the four types of dialog boxes?
Types of widgets and tradeoffs?
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Property
Function
Bulletin
Process
HTML review
• Let’s build a homepage together!