Heuristics of Understanding

Consistency

• A system is easier to learn if similar concepts are expressed in the same way
• consistency makes it easy to transfer prior knowledge to the current situation
• Types of consistency
  • aesthetic / functional
  • internal external

Familiar language and metaphors

• Speak the language of users
• user words, phrases and concepts familiar to the user, rather than system-oriented terms
• adapt the language to the target groups: children, elderly people, different cultures

What is a metaphor in UI design?

• a word or phrase designating an object used in place of another to suggest a resemblance
• the use in an interface of familiar concepts to present more abstract system concepts

Simple, aesthetic and functional design

• signal to noise ratio:
• not too crowded
• good use of color themes.
• remember that "fonts have moods"
• call the laws of Gestalt for help!

Heuristics of Action

Freedom and Control

• favor exploration before commitment
• on an e-commerce site, for example, be able to explore without having to enter a lot of information
• allow undoing different actions
• the user must feel in control

Flexibility and efficiency of use

• adaptability to domain and/or software expertise
  • shortcuts for experts, but complete menus for novices
  • several ways to go somewhere
  • multiple entry points for multiple users
• adaptability to frequency of operations
  • if something is rarely done by an non-experienced users (like setting up a printer), a linear process is more logical
  • if something is frequent, make sure the access is easy and efficient
• proactiveness
  • correct mistakes
    • simple example of "do you mean X?"
  • recommendation system
    • those who bought X also bought Y
  • making suggestions

Recognition over Recall

• limit the cognitive load
  • WIMP interaction mode
  • avoid codes, and abbreviations
  • do not assume that people will remember options(recall), make sure that the functions and options are clear (recognition) on the screen
  • remember short-term memory limits

Heuristics of Guidance

Clear status

• system status: space, process, time

Space

• in recent years, space limitations are less in effect
• sometimes free portion / paying portion (should mention limits during sign up)
• its good to provide status when the user approaches a limit (or problem), not when its too late

Process

• completed setup
  • example: Thank you, you did X
• action/next step
  • what is the next step?
  • provide the clear options
• completion
  • show the user that he/she has finished
  • for example, a completed order at checkout

Time

What is response time?

• time required between users initiating an activity and when the computer presents the results

What is think time?

• the time it takes for the user to think before performing the next action (a.k.a user response time)

• over time, users become more and more demanding of computers

• users are looking for quick response systems

• users wat to feel in control

  • slow response time gives control to the computer

• maintain low variability of the response time

  • users become more frustrated if the system sometimes runs slowly
  • explain clearly the variability of the response time

• calculate the expected duration of the delay and provide a dynamic feedback

Guide for the UI according to response time:

• <1 second: show results
• 1-3 seconds
  • a status indicator like the "spinning circle"
  • progress bar
  • countdown indication
• 3-5 seconds
  • display everything you can, as soon as you can
    • e.g. when starting an application, immediately open a window with a title
• >5 seconds:
  • announce the delay:
    • before the user selects the action(if possible), warn of the consequence
    • during the execution, indicate how long it would take

Error Prevention

1. What will happen?
   • use feedback messages to warn users of the potential consequences of their actions
2. Oh.. I do not want to go on... how can I get out here?
   • provide an exit
3. How can I enter this information?
   • add input constraints, or manage an unconstrained field
4. Have I lost everything?
   • use a state backup

Help

• help at different levels
  • global help (global process)
  • contextual help (on the buttons)
• provide tutorials, unless "walk-up-and-use" application that should be clear without additional documentation
• make access easy for beginners

Error Recovery

• Human sounding
  • make sure your error message sounds like it was written by a human for a human
• visibility
  • make sure your error message can be easily seen
• clear explanation
  • make sure your error message clearly explains what happened, that it is not encrypted or too vague
• recuperation
  • make sure your error message allows the user to recover and resolve the problem
• humility
  • make sure your error message is humble and does not blame the user
• humor
  • if appropriate, humor could help reduce frustration