Process of Interaction Design

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					Process of Interaction Design
        Overview

•What is Interaction Design?
  —Four basic activities
  —Three key characteristics
•Some practical issues
  —Who are the users?
  —What are ‘needs’?
  —Where do alternatives come from?
  —How do you choose among alternatives?
— Some general guidelines
   What is Interaction Design?

•It is a process:
   —a goal-directed problem solving activity informed
   by intended use, target domain, materials, cost, and
   feasibility
   —a creative activity
   —a decision-making activity to balance trade-offs

•It is a representation:
   —a plan for development
   —a set of alternatives & successive elaborations
     Four basic activities

There are four basic activities in Interaction
Design:
  1. Identifying needs and establishing
  requirements
  2. Developing alternative designs
  3. Building interactive versions of the designs
  4. Evaluating designs
   Three key characteristics

Three key characteristics permeate these four
activities:
   1. Focus on users early in the design and
   evaluation of the artefact
   2. Identify, document and agree specific
   usability and user experience goals
   3. Iteration is inevitable. Designers never get
   it right first time
Some practical issues
•Who are the users?

•What are ‘needs’?

•Where do alternatives come from?

•How do you choose among
alternatives?
        Who are the users?

•Not as obvious as you think:
  —those   who   interact directly with the product
  —those   who   manage direct users
  —those   who   receive output from the product
  —those   who   make the purchasing decision
  —those   who   use competitor’s products ???
    Who are the stakeholders?
                        Check-out operators


• Suppliers
• Local shop
  owners




                              Customers
Managers and owners
User categories
   Three categories of user:
       primary: frequent hands-on
       secondary: occasional or via someone else;
       tertiary: affected by its introduction, or will
        influence its purchase.

    Wider term: stakeholders
 Who are the users? (contd)
•What are their capabilities? Humans vary in
many dimensions!
•Some examples are:
  —size of hands may affect the size and
  positioning of input buttons;
  —motor abilities may affect the suitability of
  certain input and output devices;
  —height if designing a physical kiosk;
  —strength - a child’s toy requires little
  strength to operate, but greater strength to
  change batteries
        What are ‘needs’?

•Users rarely know what is possible
•Users can’t tell you what they ‘need’ to help
them achieve their goals
•Instead, look at existing tasks:
   —their context
   —what information do they require?
   —who collaborates to achieve the task?
   —why is the task achieved the way it is?
•Envisioned tasks:
   — can be rooted in existing behaviour
   — can be described as future scenarios
      Where do alternatives
      come from?
•Humans stick to what they know works
•But considering alternatives is important to ‘break
out of the box’
•Designers are trained to consider alternatives,
software people generally are not
•How do you generate alternatives?
   —‘Flair and creativity’: research & synthesis
   —Seek inspiration: look at similar products or
   look at very different products
  How do you choose among
  alternatives?
•Evaluation with users or with peers e.g. prototypes
•Technical feasibility: some not possible
•Quality thresholds: Usability goals lead to usability
criteria set early on and check regularly
    —safety: how safe?
    —utility: which functions are superfluous?
   —effectiveness: appropriate support? task
   coverage, information available
   —efficiency: performance measurements
Testing prototypes to choose
among alternatives
ISDE Lecture Activity
Lecture Activity
   Consider the design issues involved for
    the following
   A mobile phone for old people
   A mobile phone for young children
   An office phone
Lecture Activity 10 – 15 mins
   Select one of these
   Identify the key functionality required
   Identify key user & task characteristics
   Consider the design trade offs that
    might be required
   State some usability criteria that could
    be used to evaluate the design
   Produce a ‘front’ end for your device
General design Principles
   Wide range of design principles
   Examples include
        Neilsens Heuristics
        Shneiderman’s ‘Golden Rules’
        Windows Interface Guidelines
   They cover
        Guidelines for physical design
        Menu design
        Screen formatting and presentation issues

   Designers can apply these – but need to do so with care!
   Applying design guidelines alone does not lead to good design
Heuristics (after Neilsen)

   use simple and natural dialogue sequences
   speak the users language
   minimise user memory load
   be consistent
   provide feedback
   provide clearly marked exits
   provide shortcuts
   provide good error messages
   prevent errors
Shneiderman’s ‘Golden Rules’

Here is another similar list
 strive for consistency

 enable frequent users to use shortcuts

 offer informative feedback

 design dialogues to yield closure

 offer simple error handling

 permit easy reversal of actions

 support internal locus of control

 reduce short term memory load
    Windows Interface Guidelines

• Set of general principles for interface design in
Microsoft's software development documentation
   directness
   user in control
   consistency
   forgiveness
   feedback
   aesthetics
   simplicity
    Many common elements…
                     Shneiderman
Nielsen               strive for
                                           Microsoft
   use simple and                          • directness
                      consistency
   natural dialogue  enable frequent      • user in control
   sequences           users to use        • consistency
  speak the users     shortcuts           • forgiveness
   language           offer informative   • feedback
                       feedback
  minimise user                           • aesthetics
                       design dialogues
   memory load      
                       to yield closure    • simplicity
  be consistent      offer simple
  provide             error handling
   feedback           permit easy
  provide clearly     reversal of         Be consistent
   marked exits        actions
                    reduce short term
  provide             memory load
   shortcuts
  provide good
   error messages
  prevent errors
Consistency……
   important to enable user to build a reliable model of
    how the interface works
   makes the interface familiar and predictable by
    providing a sense of stability
   allows users to transfer existing knowledge to new
    tasks and focus more on tasks because they need not
    spend time trying to remember the differences in
    interaction.
   important through all aspects of the interface, names
    of commands, layout of information, and operational
    behaviour.
    Many common elements…
Nielsen                 Shneiderman             Microsoft
   use simple and         strive for          • directness
    natural dialogue        consistency
                                                • user in control
    sequences              enable frequent
                            users to use        • consistency
   speak the users
    language                shortcuts           • forgiveness
   minimise user          offer informative   • feedback
    memory load             feedback
                                                • aesthetics
    be consistent          design dialogues

                            to yield closure    • simplicity
   provide feedback
                           offer simple
   provide clearly         error handling
    marked exits
                           permit easy
   provide shortcuts       reversal of
    provide good
                                                 Reduce memory
                           actions
    error messages         support internal     load
   prevent errors          locus of control
                           reduce short
                            term memory
                            load
Minimise user memory load
   Basic rule: don’t expect the user to remember what
    has already been done, make this visible at the
    interface
   If a command is made up of a number of pieces of
    data entered by the user in sequence, display these
    rather than expect the user to remember the data
    already entered
   Help the user remember where they are in a
    transaction sequence – Menu 2/5 Step 1 - 4
   Will cover design implications later
Feedback: American Airlines
site


                   Place in transaction sequence

             Data previously entered
    Many common elements…
Nielsen             Shneiderman            Microsoft
  use simple and  strive for             • directness
   natural dialogue    consistency
                                           • user in control
   sequences          enable frequent
                       users to use        • consistency
  speak the users     shortcuts           • forgiveness
   language            offer informative
                                          • feedback
  minimise user       feedback            • aesthetics
   memory load        design dialogues
                                           • simplicity
  be consistent       to yield closure
  provide            offer simple
                       error handling
   feedback
                      permit easy
  provide clearly     reversal of
   marked exits        actions
   provide
                                           Feedback to user
                     support internal
   shortcuts           locus of control
  provide good       reduce short
   error messages      term memory
                       load
  prevent errors
    Feedback from the system
   Every action the user makes should produce a perceptible response.
   The intention is to reduce user uncertainty that the system has:
      received the last input,

      is currently doing something about it,

      or is waiting for the next input.

   Commands should result in some visible change to the interface
      E.g ‘mail has been sent’ in response to a ‘Send’ command

      Presentation of objects on screen updated to reflect their

        current state
   Task analysis should enable appropriate information to be identified
    as feedback for a specific task
Feedback: Response Time

   Response time for feedback should be appropriate to the type
    of user action:
      e.g.    response to keystroke - instantaneous;
               response to command input - may take longer
   Provide ‘system busy’ feedback if time will exceed a few
    seconds or is unpredictable
   Provide indication of how many transactions remain, for
    example as a bar chart or as a percentage.
   This largely disappeared as a problem with fast single user PCs
    and has re-appeared with distributed web-based applications
    Many common elements…
Nielsen                Shneiderman             Microsoft
   use simple and        strive for          • directness
    natural dialogue       consistency         • user in control
    sequences             enable frequent     • consistency
                           users to use
   speak the users        shortcuts           • forgiveness
    language                                   • feedback
                          offer informative
   minimise user          feedback            • aesthetics
    memory load            design dialogues
                       
                                               • simplicity
   be consistent          to yield closure
   provide               offer simple
    feedback               error handling
                           permit easy
   provide clearly    
                           reversal of
    marked exits           actions             Appropriate user
   provide               support internal
    shortcuts              locus of control    support
   provide good          reduce short
    error messages         term memory
                           load
   prevent errors
Appropriate user support

   HELP messages
      important to recognise different types of help;

      should be available when required and context-specific;

      can the user get help about what responses are possible at a

       given point in a dialogue.
   ERROR messages
      should explain what is wrong and what corrective action is

       required;
      should use ‘jargon’ familiar to the user;

      often this support is poorly designed in terms of what

       information is given to the user.
    Many common elements…
Nielsen             Shneiderman            Microsoft
  use simple and  strive for             • directness
   natural dialogue    consistency
                                           • user in control
   sequences          enable frequent
                       users to use        • consistency
  speak the users     shortcuts           • forgiveness
   language            offer informative
                                          • feedback
  minimise user       feedback            • aesthetics
   memory load        design dialogues
                                           • simplicity
  be consistent       to yield closure
  provide            offer simple
                       error handling
   feedback
                      permit easy
  provide clearly     reversal of
   marked exits        actions
   provide
                                           Flexibility
                     support internal
   shortcuts           locus of control
  provide good       reduce short
   error messages      term memory
                       load
  prevent errors
Flexibility

   Measure of how well a dialogue can cater for
    different levels of user skill.
   Provide alternative means of achieving the same goal
    which match different models of how the interface
    works.
      e.g. word selection: cursor to start of word and

        double click, click and drag, click and shift-click.
      e.g. word deletion: word highlighted and Control

        +X key, select ‘Cut’ menu option, backspace.
Flexibility

   Adapt to the skill level of the user by:
     providing accelerators:
       allow user to answer ahead,
       provide key bindings for menu options;
      providing macro facility;

      accepting abbreviations for command words;

      accepting synonyms (alternative names);

      allowing user to choose level of instructions or

       help.
    Many common elements…
Nielsen             Shneiderman            Microsoft
  use simple and  strive for             • directness
   natural dialogue    consistency
                                           • user in control
   sequences          enable frequent
                       users to use        • consistency
  speak the users     shortcuts           • forgiveness
   language            offer informative
                                          • feedback
  minimise user       feedback            • aesthetics
   memory load        design dialogues
                                           • simplicity
  be consistent       to yield closure
  provide            offer simple
                       error handling
   feedback
                      permit easy
  provide clearly     reversal of
   marked exits        actions
   provide
                                           User in control
                     support internal
   shortcuts           locus of control
  provide good       reduce short
   error messages      term memory
                       load
  prevent errors
User in control

   user initiates actions, not the computer or software
   use techniques to automate tasks, but implement
    them in a way that allows the user to chose or
    control the automation.
   users must be able to personalize aspects of the
    interface, such as colour, fonts, or other options
Minimal user input

   Balance between number of keystrokes or mouse
    movements/clicks and memory load.
   Reducing keying errors increases speed of data entry.
   Allow selection from a list rather than typing in a value
    (recognise rather than recall).
   Edit a command that has produced an error rather than retyping
    the command.
   Do not request input of information which can be derived
    automatically or which has been entered previously.
   Use default values.
    Menus
   Usually a collection of actions, structured into a list from which
    a user chooses
   Actions applied to objects
      Explicitly selected by user – format + font… [selected text]

      Implicitly assumed by system – print [current file]

      Pop-up menu over selected object shows common actions

        on that object
   Actions may be represented
      by text (e.g pull-down menu)

      by icons (e.g toolbar)

   Actions completed
      Immediately by selecting menu item

      Following collection of more data from user (via a dialogue

        box)
    Overloading menus
   Most common Windows applications use an ‘anything, anytime’
    approach – ie all commands are available to the user at all
    times
   Leads to large, cumbersome menu structures where the user
    can forget how to find a particular command
   Toolbars attempt to provide shortcuts to frequently used items
       order of icons in toolbars different from items in pull-down
        menus representing same actions
   Many CAD systems use an alternative, moded approach where a
    general type of operation, or task is selected
       Only a restricted set of menus relevant to that operation are
        displayed
   This approach is now used in some MS applications
Menu Structure
‘Structures should reflect users expectations.. and support users
    flow of work’ (ISO 9241/14)
Priorities
   Conventional categories (file, edit,…)
   Use of dividers to break menus into groups
   Logical groups of related actions (cut,copy,paste)
 Arbitrary groups

       consistently ordered, numerically or alphabetically
Sequencing options within
groups
   consistency - use the same relative order of items where the
    group is presented again
   importance - place important items first in the group
   conventional order e.g days of the week
   order of use - e.g ‘copy’ preceeds ‘paste’
   frequency of use
      if frequency of option is known, place frequent items first

   alphabetical order

   What ordering rules have been applied in the next slide?
Functional Objectives with
Screen Layout
   arrange items on screen to give highest
    probability of elicting an acceptable
    level of human performance
   the user will be able
       extract information she is seeking
       identify related groups of information
       distinguish exceptional items (warnings
        and error messages)
       determine what action is necessary
Formatting recommendations

   split strings more than 6 alpha numerics into smaller groups
          (bad)                        (good)
          ABBA347686A2             ABBA 347686 A2
          ABBA456388A3             ABBA 456388 A3
   identical data should be presented in the same way even if
    varaitions in input format are tolerated
          30 11 95
          30 Nov 1995      -> 30/11/95 (for example)
          30 11 1995
          30th nov 95
     Formatting recommendations

   data should be presented in full version
    even if abbreviated input allowed,
    provide feedback to user

       Party:[        ]
       Party:[ ch,cai] Chemical Bank, Cairo
Formatting recommendations

   numeric codes displayed with right justification
          47321                  47321
          539                      539
          67                         67
          482645               482645
   lists of numeric with decimal points should be aligned around
    the point
              34.723
              43.908
          2341.5
Labeling in screen design

   descriptive title or phrase adjacent to a group of
    related items or information
   ensure labels are meaningful to the user
   labelling should be visually distinct from the data
   data labelling should not be able to be confused with
    help messages or command descriptions
Labeling in screen design

   use consistent relationship between
    labels and data being described
       e.g. above and left justified
              Name:
              [             ]

   include units in label to reduce
    ambiguity
       e.g. Weight( Kg):
            [      ]
Aesthetic issues
   Design is valued for its fitness to a particular user
    and task
   Design aesthetics is intended to make the product or
    system appear attractive & appealing
   Nielsen advocates Simplicity – particularly for
    Website design
   However careful use of colour, graphics and
    formatting can make the design more aesthetically
    pleasing
      Need to get the right balance
Style guides and sources of
design guidance
   Plenty of these….
   Manufacturers
   Web-based style guides e.g Yale Style Manual
       http://info.med.yale.edu/caim/manual/index.html
   List of style guides
      http://www.indiana.edu/~iirg/REFERENCES/guidel

       ines.html

				
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