1. Design, prototyping and construction

2. The Task-Centered Design Process
figure out who's going to use the system to do what
choose representative tasks for task-centered design
plagiarize
rough out a design
think about it
create a mock-up or prototype
test it with users
iterate
build it
track it
change it

3. Overview Prototyping and construction Conceptual design
Physical design
Tool support

4. Two guidelines for design
1. Provide a good conceptual model
allows user to predict the effects of our actions
problem:
designer’s conceptual model communicated to user through system image:
appearance, written instructions, system behaviour through interaction,
transfer, idioms and stereotypes
if system image does not make model clear and consistent, user will develop wrong conceptual model

5. Two guidelines for design (continued)
2. Make things visible
relations between user’s intentions, required actions, and results are
sensible
non arbitrary
meaningful
visible affordances, mappings, and constraints
use visible cultural idioms
reminds person of what can be done and how to do it

6. Prototyping and construction
What is a prototype?
Why prototype?
Different kinds of prototyping low fidelity high fidelity
Compromises in prototyping vertical horizontal
Construction

7. What is a prototype?
In other design fields a prototype is a small-scale model:
a miniature car a miniature building or town

8. What is a prototype?
In interaction design it can be (among other things):
a series of screen sketches a storyboard, i.e. a cartoon-like series of scenes a Powerpoint slide show a video simulating the use of a system a lump of wood (e.g. iphone) a cardboard mock-up a piece of software with limited functionality written in the target language or in another language

9. Why prototype?
Evaluation and feedback are central to interaction design
Stakeholders can see, hold, interact with a prototype more easily than a document or a drawing
Team members can communicate effectively
You can test out ideas for yourself
It encourages reflection: very important aspect of design
Prototypes answer questions, and support designers in choosing between alternatives

10. What to prototype? Technical issues Work flow, task design
Screen layouts and information display
Difficult, controversial, critical areas

11. Low-fidelity Prototyping
Uses a medium which is unlike the final medium, e.g. paper, cardboard
Is quick, cheap and easily changed
Examples: sketches of screens, task sequences, etc ‘Post-it’ notes storyboards ‘Wizard-of-Oz’

14. Storyboards
Often used with scenarios, bringing more detail, and a chance to role play
It is a series of sketches showing how a user might progress through a task using the device
Used early in design

15. Sketching Sketching is important to low-fidelity prototyping
Don’t be inhibited about drawing ability. Practice simple symbols

16. Using index cards Index cards (3 X 5 inches)
Each card represents one screen
Often used in website development

17. ‘Wizard-of-Oz’ prototyping
The user thinks they are interacting with a computer, but a developer is responding to output rather than the system.
Usually done early in design to understand users’ expectations
What is ‘wrong’ with this approach?
User
>Blurb blurb
>Do this
>Why?

18. High-fidelity prototyping
Uses materials that you would expect to be in the final product.
Prototype looks more like the final system than a low-fidelity version.
For a high-fidelity software prototype common environments include Macromedia Director, Visual Basic, and Smalltalk.
Danger that users think they have a full system…….see compromises

19. Compromises in prototyping
All prototypes involve compromises
For software-based prototyping maybe there is a slow response? sketchy icons? limited functionality?
Two common types of compromise
‘horizontal’: provide a wide range of functions, but with little detail
‘vertical’: provide a lot of detail for only a few functions
Compromises in prototypes mustn’t be ignored. Product needs engineering

20. Construction
Taking the prototypes (or learning from them) and creating a whole
Quality must be attended to: usability (of course), reliability, robustness, maintainability, integrity, portability, efficiency, etc
Product must be engineered
Evolutionary prototyping
‘Throw-away’ prototyping

21. Conceptual design: from requirements to design
Transform user requirements/needs into a conceptual model
“a description of the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended”
Don’t move to a solution too quickly. Iterate, iterate, iterate
Consider alternatives: prototyping helps

22. Three perspectives for a conceptual model
Which interaction mode?
How the user invokes actions
Activity-based: instructing, conversing, manipulating and navigating, exploring and browsing.
Object-based: structured around real-world objects

23. Three perspectives for a conceptual model
Which interaction paradigm?
desktop paradigm, with WIMP interface (windows, icons, menus and pointers),
ubiquitous computing
pervasive computing
wearable computing
mobile devices and so on.
Is there a suitable metaphor?
(contd)….

24. Is there a suitable metaphor?
Interface metaphors combine familiar knowledge with new knowledge in a way that will help the user understand the product.
Three steps: understand functionality, identify potential problem areas, generate metaphors
Evaluate metaphors:
How much structure does it provide?
How much is relevant to the problem?
Is it easy to represent?
Will the audience understand it?
How extensible is it?

25. Interface metaphors
Interface designed to be similar to a physical entity but also has own properties
e.g. desktop metaphor, web portals
Can be based on activity, object or a combination of both
Exploit user’s familiar knowledge, helping them to understand ‘the unfamiliar’
Conjures up the essence of the unfamiliar activity, enabling users to leverage of this to understand more aspects of the unfamiliar functionality

26. Benefits of interface metaphors
Makes learning new systems easier
Helps users understand the underlying conceptual model
Can be very innovative and enable the realm of computers and their applications to be made more accessible to a greater diversity of users

27. Problems with interface metaphors
Break conventional and cultural rules
e.g. recycle bin placed on desktop
Can constrain designers in the way they conceptualize a problem space
Conflict with design principles
Forces users to only understand the system in terms of the metaphor
Designers can inadvertently use bad existing designs and transfer the bad parts over
Limits designers’ imagination in coming up with new conceptual models

34. Expanding the conceptual model
What functions will the product perform?
What will the product do and what will the human do (task allocation)?
How are the functions related to each other?
sequential or parallel?
categorisations, e.g. all actions related to telephone memory storage
What information needs to be available?
What data is required to perform the task?
How is this data to be transformed by the system?

35. Physical design: getting concrete
Considers more concrete, detailed issues of designing the interface
Iteration between physical and conceptual design
Guidelines for physical design
Nielsen’s heuristics
Cooper’s About Face 2.0
Styles guides: commercial, corporate
decide ‘look and feel’ for you
widgets prescribed, e.g. icons, toolbar

36. Alan Cooper’s Excise Traps
Don’t force the user to go to another window to perform a function that affects this window
Don’t force the user to remember where he put things in the hierarchical file system
Don’t force the user to resize windows unnecessarily
Don’t force the user to move windows
Don’t force the user to reenter personal settings

37. Cooper’s Excise Traps
Don’t force the user the fill fields to satisfy some arbitrary measure of completeness
Don’t force the user to ask permission to make changes.
Don’t ask the user to confirm his actions.
Don’t let the user’s actions result in an error.

38. Direct manipulation Drag and drop files
Direct manipulation captures the idea of “direct manipulation of the object of interest” (Shneiderman 1983: p. 57), which means that objects of interest are represented as distinguishable objects in the UI and are manipulated in a direct fashion.
Characteristics:
Visibility of the object of interest.
Rapid, reversible, incremental actions.
Replacement of complex command language syntax by direct manipulation of the object of interest.
Drag and drop files

39. One of the earliest commercially available direct manipulation interfaces was MacPaint

40. Direct Manipulation Advantages Visually presents task concepts.
Easy to learn.
Errors can be avoided more easily.
Encourages exploration.
High subjective satisfaction.
Recognition memory (as opposed to cued or free recall memory)  
Disadvantages
May be more difficult to program.
Not suitable for small graphic displays.
Spatial and visual representation is not always preferable.
Metaphors can be misleading since the “the essence of metaphor is understanding and experiencing one kind of thing in terms of another” (Lakoff and Johnson 1983: p. 5), which, by definition, makes a metaphor different from what it represents or points to.
Compact notations may better suit expert users.

41. “Don’t Mode me in” UNIX ‘vi’ is an example of “evil” modes
same actions have different meanings depending on context
‘edit’ replaces your file with ‘t’
Paint programs are a good example of “good” modes.
Modes are visible

42. Rules for modes Use modes consistently
Do not initiate modes unexpectedly
Make modes visible
Make it easy to escape modes
… without consequences.

43. Physical design: getting concrete
Different kinds of widget (dialog boxes, toolbars, icons, menus etc)
menu design
icon design
screen design
information display

44. Icon design Good icon design is difficult
Meaning of icons is cultural and context sensitive
Some tips:
always draw on existing traditions or standards
concrete objects or things are easier to represent than actions
From clip art, what do these mean to you?

45. Screen design Two aspects: How to split across screens
moving around within and between screens
how much interaction per screen?
Individual screen design
white space: balance between enough information/interaction and clarity
grouping items together: separation with boxes? lines? colors?

46. Screen design: individual screen design
Draw user attention to salient point, e.g. colour, motion, boxing
Animation is very powerful but can be distracting
Good organization helps: grouping, physical proximity
Trade off between sparse population and overcrowding

47. Principles of Visual interface design
Avoid visual noise and clutter
Use contrast, similarity, and layering to distinguish and organize elements
Provide visual structure and flow at each level of organization
Use cohesive, consistent, and contextually appropriate imagery
Integrate style and function comprehensively and purposefully
Alan Cooper, Robert M. Reimann. About Face 2.0: The Essentials of Interaction Design. Page 227.

48. Organization of Screen Elements
Balance
Symmetry
Regularity
Predictability
Sequentiality
Economy
Unity
Proportion
Simplicity
Groupings

49. Balance
Equal weight of screen elements
Left to right, top to bottom

50. Balance
Unstable

51. Balance Left column processed - Right column noted as same
Both columns need to be understood by visual processing system

52. Symmetry
Replicate elements left and right of the center line

53. Symmetric
Asymmetric

54. Regularity
Create standard and consistent spacing on horizontal and vertical alignment points

55. Regularity Left column processed - 2 right columns noted as same
Location & size of each object processed

56. Predictability
Put things in predictable locations on the screen

57. Predictable Spontaneous Icon File Edit View Insert Window Help
Kung Foo
Search for Movies
Cancel OK
Enter Keywords:
Grasshopper
Old blind guy
Predictable
Icon
File Edit View Insert Window Help
Kung Foo
Search for Movies
Cancel OK
Enter Keywords:
Grasshopper
Old blind guy
Spontaneous

58. Predictability User expects title & menu bar on top of screen
Visual scene needs to be completely processed - objects not in expected places
Icon
Search for Movies
File Edit View Insert Window Help
Enter Keywords:
Kung Foo
Grasshopper
Old blind guy OK
Cancel OK
Icon
Enter Keywords:
Kung Foo
Grasshopper
Old blind guy
File Edit View Insert Window Help
Search for Movies
Cancel

59. Sequentiality Guide the eye through the task in an obvious way
The Eye is attracted to:
bright elements over less bright
Isolated elements over grouped
graphics before text
color before monochrome
saturated vs. less saturated colors
dark areas before light
big vs. small elements
unusual shapes over usual ones

60. Screen design: splitting functions across screens
Task analysis as a starting point
Each screen contains a single simple step?
Frustration if too many simple screens
Keep information available: multiple screens open at once

61. Membership Form
Name:
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Sequential
Membership Form
Name:
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Address:
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Total:
Random

62. Economy
Use as few styles, fonts, colors, display techniques, dialog styles, etc., as possible

63. Membership Form Name: Dues: Address: Pubs: City: Total: State: Zip: OK
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Economical
Membership Form
Name:
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Zip: OK
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Busy

64. Unity Make items appear as a unified whole (for visual coherence)
Use similar shapes, sizes, or colors
Leave less space between screen elements than at the margin of the screen

65. Unity
Fragmentation

66. Proportion
Create groupings of data or text by using aesthetically pleasing proportions

67. Pleasing Proportions Square - 1:1 Square Root of 2 - 1:1.414
Golden Triangle - 1:1.618
Square Root of 3 - 1:1.732
Double Square - 1:2

68. Simplicity Minimize the number of aligned points
Use only a few columns to display screen elements
Combine elements to minimize the number of screen objects
Within limits of clarity

69. Simplicity Only four alignments need to be processed
A total of nine alignments need to be processed
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70. Size::
Preserve Proportions % of original height % of original width
Simple
Size:
Uniformity:
Height:
Width:
Preserve Proportions % of original % of original
Complex

71. Groupings
Use visual arrangements to provide functional groupings of screen elements
Align elements in a group
Evenly space elements in a group
Provide separation between groups
Use additional group elements sparingly
color & borders add complexity

72. Simple Grouping Similar elements aligned vertically
Vertical distance between similar objects small
Membership Form
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73. Boxed Grouping Boxes add additional complexity to form
Spatial arrangement adequate
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74. Background Grouping Color adds additional visual complexity
Spatial arrangement adequate
Membership Form
Name:
Dues:
Address:
Pubs:
City:
Total:
State:
Zip: OK
Cancel

75. Alignment Grids and the User’s Logical Path
Align labels. Labels for controls stacked vertically should be aligned with each other; left-justification is easier for users to scan than right justification, although the latter may look visually cleaner-if the input forms are the same size. (Otherwise, you get a Christmas tree, ragged-edge effect on the left and right.)
Align within a set of controls. A related group of check boxes, radio buttons, or text fields should be aligned according to a regular grid.
Align across controls. Aligned controls (as described previously) that are grouped together with other aligned controls should all follow the same grid.
Follow a regular grid structure for larger-scale element groups, panes, and screens, as well as for smaller grouping of controls.
Alan Cooper, Robert M. Reimann. About Face 2.0: The Essentials of Interaction Design. (Wiley, 2003). Page 230.

76. Aligned grid layout

77. Screen-based Controls
Widgets
elements of screen displays
interaction toolkits
ready-made interaction objects
predefined behaviors
customizable properties

78. Functions of Widgets Selecting options and commands
Entering and editing data values
Displaying data

79. Kinds of Widgets Buttons Text entry/read-only Selection
Combination entry/selection
Specialized or custom
Presentation

80. Design issues
Labels and graphics
Layout and organization
Activation

81. Labels and Graphics Use labels and captionsOK
Use labels and captions
Use standard names when appropriate
Use regular system font
Clearly tie the text to the control
Maintain consistent heights and widths
Use common shapes (mostly rectangles)
Pick icons that map to the actions
Supplement icons with text descriptions

82. Layout and Organization
Provide adequate spacing
Limit the number of controls on one screen
Keep related controls together
Use visual enclosure of groups where appropriate

83. Aligning list boxes
Align list boxes vertically rather than horizontally.
Horizontally aligned list boxes are more difficult for the user to use, as the controls cannot be scanned easily.

84. Aligning radio buttons
This :
Not this:

85. Activation Provide keyboard equivalents Provide feedback for actions
Control activation
Movement among controls within a screen
Provide feedback for actions
Gray out unavailable choices

86. Buttons Initiates an action Always visible
to activate a command (an alternate to menu choice or command line entry).
to display another window or menu selection
Always visible
provides convenient access to frequently-used commands
standard shapes and screen location for similar commands.
Logical organization

87. Microsoft’s Button Types
Buttons
Types
Command buttons -- text as labels
Bar buttons (menu buttons)
-- graphics and/or text as labels
Radio buttons
Next
Microsoft’s Button Types

88. Which one is better? Plan Choice: Plan Choice Plan Choice: Limited
Basic
Superior
Premium
Plan Choice
Plan Choice:
Limited
Limited
Basic
Basic
Superior
Superior
Premium
Premium

89. Button Design Issues Labels Shapes and Graphics Location and layout
Organization
Activation

90. Buttons -- labels Use standard button labels when available
Provide meaningful action description
Use regular system font
unless for some special purposes
Center the label text
Provide consistency across all screens

91. Buttons --shape and graphics
Use rectangular shape whatever possible
Maintain consistent button heights and widths
Design graphics/icons that have natural mapping to the actions
Enhanced graphics with text description

92. Buttons -- Organization
Maintain consistency in button locations across screens and windows
provide adequate spacing between buttons and other screen controls
Restrict the number of buttons on one screen
Follow standards
Keep related buttons together

93. Buttons -- Activation Consider different actions for
mouse enter/exit .. mouse down/up/
Consider keyboard equivalents for actions
Provide feedback for actions
highlight the button when the button is selected
Gray out unavailable choices.

94. Text Entry/Read-Only Controls
Text boxes
Editable/read-only (fields vs. labels)
single line/multiple lines
fixed size/resizable
fixed length/variable lengths
visual box/non-visual box
scrollable /non-scrollable
Properties
background/foreground colors
sizes/fonts/styles of text
alignments

95. Text Box Design Provide descriptive caption
Logical arrangement of multiple fields
Consider the cursor movement from one field to another.
Provide large enough boxes for fixed-length data
Select reasonable fonts/sizes/colors
Design highlight to attract attention

96. Selection Controls Present all options or choices on the screen
Radio Buttons
Check Boxes
Palettes
List Boxes
Combo Boxes
Drop-Down/Pop-Up
Single Selection/Multiple Selection?

97. Selection Design Choice Description Organization Activation
Meaningful and clear description for the value or effects of the choice
Use single line of text whenever possible
Organization
Meaningful order of choices
Consider adding a enclosure box
Activation
Provide visual feedback
Provide default values

98. List Box or Combo Box? List box Combo box unlimited number of choices
possible multiple choices
consumes screen space
can be set to different size
easy to see the choices
Combo box
unlimited number of choices
highlight the selection
conserves screen space
Extra step to display all the choices

99. More Selection Controls
Spin Boxes
Attached Combo Boxes
Left Margin:
0.5”
Font Style:
Regular
Regular
Italic
Bold
Bold Italic

100. Other Controls Scroll Bars Sliders Toggle Switches Tab pages
Contain tabbed divider pages

101. Presentation Controls
Provide additional information to screen elements
Tooltips
a small popup window attached to an object
shows only when the mouse moves over the object
Static Text Fields -- labels
Group Boxes
Combined controls in one box
Progress Indicators

102. Message Design