Usability

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Usability Heuristics
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Heuristic a definition

• As an adjective, heuristic (pronounced
  hyu-RIS-tik) and from the Greek "heuriskein"
  meaning "to discover") pertains to the process of
  knowing by trying rather than by following some
  preestablished formula. (Heuristic can be
  contrasted with algorithm) The term seems to
  have two usages
• 1) Describing an approach to learning by trying
  without necessarily having an organized
  hypothesis or way of proving that the results
  proved or disproved the hypothesis. That is,
  "seat-of-the-pants" or "trial-by-error" learning.
• 2) Pertaining to the use of the general
  knowledge gained by experience, sometimes
  expressed as "using a rule-of-thumb." (However,
  heuristic knowledge can be applied to complex as
  well as simple everyday problems. Human chess
  players use a heuristic approach.)
• As a noun, a heuristic is a specific
  rule-of-thumb or argument derived from experience.

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The top 10 recommended usability heuristics

• Visibility of system status
• Match between system and the real world
• User control and freedom
• Consistency and standards
• Error prevention
• Recognition rather than recall
• Flexibility and efficiency of use
• Aesthetic and minimalist design
• Help users recognize, diagnose, and recover from
  errors
• Help and documentation

according to Nielsen
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1. Visibility of system status

• The system should always keep users informed
  about what is going on, through appropriate
  feedback within reasonable time.

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1.1 Feedback

• What user is doing
• How input being interpreted
• Restate user input
• Remove when operation is completed
• Response time
• Latency Reduction
• Use indicatorsstatus mechanisms
• System failure
• Graceful degradation

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2. Match between system and the real world

• The system should speak the users' language, with
  words, phrases and concepts familiar to the user,
  rather than system-oriented terms. Follow
  real-world conventions, making information appear
  in a natural and logical order.

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2.1 Speak the users language

• Use users native language
• Mappings and metaphors
• Use user task language
• Metaphors
• making the abstract seem familiar

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2.2 Simple and natural dialog

• Anticipate users wants and needs
• Match the user task
• Less is more reduce complexity
• use defaults
• templates, etc
• Present info only when needed for task

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2.3 What is a metaphor?

• Examples
• Electronic Mail (Email)
• Documents
• Desktops
• Notebooks
• Cards

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2.31 Three Basic Metaphors

• Manipulation/physical objects
• Navigation
• Conversational

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2.32 Using metaphors

• Must correlate well with the abstract concept
• Models should suggest how to use an object.

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3. User control and freedom

• Users often choose system functions by mistake
  and will need a clearly marked "emergency exit"
  to leave the unwanted state without having to go
  through an extended dialogue. Support undo and
  redo.

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4. Consistency and standards

• Users should not have to wonder whether different
  words, situations, or actions mean the same
  thing. Follow platform conventions.

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4.1 Consistency

• Internal and external consistency
• Levels
• shortcut keys
• small visible structures
• overall look
• suite of products
• in-house consistency
• platform consistency

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4.2 Grids

• Focus
• readability
• higher-level structure

http//www.poynterextra.org/eyetrack2004/viewing.h
tm
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5. Error prevention

• Even better than good error messages is a careful
  design which prevents a problem from occurring in
  the first place.

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6. Recognition rather than recall

• Make objects, actions, and options visible. The
  user should not have to remember information from
  one part of the dialogue to another. Instructions
  for use of the system should be visible or easily
  retrievable whenever appropriate.

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6.1 Minimize the users memory load

• Display dialogue
• Use multi-modal displays
• Choose from items generated
• Provide formats
• Give examples

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7. Flexibility and efficiency of use

• Accelerators -- unseen by the novice user -- may
  often speed up the interaction for the expert
  user such that the system can cater to both
  inexperienced and experienced users. Allow users
  to tailor frequent actions.

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7.1 Flexibility

• Flexibility
• dealing with unanticipated situations
• support for dynamic layouts (resize)

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7.2 Consistency

• Consistent application
• corporate logo
• look and feel
• placement, appearance, meaning
• layout of dialog boxes

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7.3 Shortcuts

• Support efficiency of the user
• Help experienced users
• Type-ahead
• Jump directly to where user wants to go
• Reuse interaction history

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8. Aesthetic and minimalist design

• Dialogues should not contain information which is
  irrelevant or rarely needed. Every extra unit of
  information in a dialogue competes with the
  relevant units of information and diminishes
  their relative visibility.

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8.1 Simple rules

• Graphic design and color
• Use Gestalt rules
• Proximity
• Similarity
• Closure
• Continuity
• Symmetry
• Do not overdo color
• Readability

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• Graphic layout structure
• Fitts Law the time to acquire a target is a
  function of the distance to and size of the
  target.
• Grids

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9. Help users recognize, diagnose, and recover
from errors

• Error messages should be expressed in plain
  language (no codes), precisely indicate the
  problem, and constructively suggest a solution.

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9.1 Good error messages

• Use clear language and avoid codes
• Be precise not vague
• Be constructive and help user
• Be polite and not intimidate
• Multi-level messages
• Give shorter message first, click for more

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A file that big? It might be very useful. But now
it is gone. The Web site you seek cannot be
located but endless others exist Chaos reigns
within. Reflect, repent, and reboot. Order shall
return. ABORTED effort Close all that you have.
You ask way too much. First snow, then
silence. This thousand dollar screen dies so
beautifully. With searching comes loss and the
presence of absence "My Novel" not found. The
Tao that is seen is not the true Tao, until You
bring fresh toner. Windows NT crashed. I am the
Blue Screen of Death. No one hears your
screams. Serious error. All shortcuts have
disappeared. Screen. Mind. Both are blank.
Error Message Haiku
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(No Transcript)
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9.2 Prevent errors

• Protect users work
• Ask for confirmation -(
• Designers avoid modes
• Status indicators
• Avoid invisible navigation

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9.3 Common Design Mistakes

• Arbitrary component positions
• Arbitrary component dimensions
• button sizes
• Random window sizes and layouts
• dialog boxes
• Unrelated icon sizes and imagery
• Inconsistent control presentations
• Inconsistent visual language

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10. Help and documentation

• Even though it is better if the system can be
  used without documentation, it may be necessary
  to provide help and documentation. Any such
  information should be easy to search, focused on
  the user's task, list concrete steps to be
  carried out, and not be too large.

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In Class exercise

• Identify and delegate products related to your
  project.
• Begin planning Heuristic Evaluation Assignment
  and Presentation.

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reference

• http//www.useit.com/papers/heuristic/
• Jakob Nielsen's Online Writings on Heuristic
  Evaluation
• How to conduct a heuristic evaluation
• A list of ten recommended heuristics for usable
  interface design
• A more detailed discussion of the
  characteristics of the usability problems found
  by heuristic evaluation
• How to rate the severity of the usability
  problems
• Why uptake in industry has been so fast for
  heuristic evaluation (note this essay is about
  technology transfer and not a tutorial article
  like the rest of this list)

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Command Lines and GUIS

• http//www.cryptonomicon.com/beginning.html

• Launchbar, quicksilver, etc.