Design, prototyping and construction

The Task-Centered Design Processfigure out who's going to use the system to do what choose representative tasks for task-centered designplagiarizerough out a designthink about itcreate a mock-up or prototypetest it with usersiteratebuild ittrack itchange it

Overview

Prototyping and construction

Conceptual design

Physical design

Tool support

Two guidelines for design1. Provide a good conceptual modelallows user to predict the effects of our actionsproblem: designers 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

Two guidelines for design (continued)2. Make things visiblerelations between users intentions, required actions, and results aresensiblenon arbitrarymeaningful visible affordances, mappings, and constraints use visible cultural idioms reminds person of what can be done and how to do it

Prototyping and construction

What is a prototype? Why prototype?Different kinds of prototyping low fidelity high fidelityCompromises in prototyping vertical horizontalConstruction

What is a prototype?

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

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

Why prototype?

Evaluation and feedback are central to interaction designStakeholders can see, hold, interact with a prototype more easily than a document or a drawingTeam members can communicate effectivelyYou can test out ideas for yourself It encourages reflection: very important aspect of design Prototypes answer questions, and support designers in choosing between alternatives

What to prototype?

Technical issues

Work flow, task design

Screen layouts and information display

Difficult, controversial, critical areas

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

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

Sketching

Sketching is important to low-fidelity prototyping

Dont be inhibited about drawing ability. Practice simple symbols

Index cards (3 X 5 inches)

Each card represents one screen

Often used in website development

Using index cards

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 expectationsWhat is wrong with this approach?

>Blurb blurb>Do this>Why?User

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

Compromises in prototyping

All prototypes involve compromisesFor 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 functionsCompromises in prototypes mustnt be ignored. Product needs engineering

Construction

Taking the prototypes (or learning from them) and creating a wholeQuality must be attended to: usability (of course), reliability, robustness, maintainability, integrity, portability, efficiency, etcProduct must be engineeredEvolutionary prototypingThrow-away prototyping

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 Dont move to a solution too quickly. Iterate, iterate, iterateConsider alternatives: prototyping helps

Three perspectives for a conceptual model

Which interaction mode?How the user invokes actionsActivity-based: instructing, conversing, manipulating and navigating, exploring and browsing. Object-based: structured around real-world objects

Three perspectives for a conceptual model

Which interaction paradigm? desktop paradigm, with WIMP interface (windows, icons, menus and pointers),ubiquitous computingpervasive computingwearable computingmobile devices and so on.

Is there a suitable metaphor?(contd).

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?

Interface metaphorsInterface designed to be similar to a physical entity but also has own propertiese.g. desktop metaphor, web portalsCan be based on activity, object or a combination of bothExploit users 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

Benefits of interface metaphorsMakes learning new systems easierHelps users understand the underlying conceptual modelCan be very innovative and enable the realm of computers and their applications to be made more accessible to a greater diversity of users

Problems with interface metaphors Break conventional and cultural rulese.g. recycle bin placed on desktopCan constrain designers in the way they conceptualize a problem spaceConflict with design principlesForces users to only understand the system in terms of the metaphorDesigners can inadvertently use bad existing designs and transfer the bad parts overLimits designers imagination in coming up with new conceptual modelshttp://www.cooper.com/articles/art_myth_of_metaphor.htm

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 storageWhat information needs to be available?What data is required to perform the task? How is this data to be transformed by the system?

Physical design: getting concrete

Considers more concrete, detailed issues of designing the interfaceIteration between physical and conceptual designGuidelines for physical designNielsens heuristicsCoopers About Face 2.0Styles guides: commercial, corporate decide look and feel for youwidgets prescribed, e.g. icons, toolbar

Alan Coopers Excise Traps

Dont force the user to go to another window to perform a function that affects this windowDont force the user to remember where he put things in the hierarchical file systemDont force the user to resize windows unnecessarilyDont force the user to move windowsDont force the user to reenter personal settings

Coopers Excise Traps

Dont force the user the fill fields to satisfy some arbitrary measure of completenessDont force the user to ask permission to make changes.Dont ask the user to confirm his actions.Dont let the users actions result in an error.

Direct manipulationDirect 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

One of the earliest commercially available direct manipulation interfaces was MacPaint

Direct ManipulationAdvantages 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.

Dont Mode me inUNIX vi is an example of evil modessame actions have different meanings depending on contextedit replaces your file with tPaint programs are a good example of good modes.Modes are visible

Rules for modesUse modes consistentlyDo not initiate modes unexpectedlyMake modes visibleMake it easy to escape modes without consequences.

Physical design: getting concrete

Different kinds of widget (dialog boxes, toolbars, icons, menus etc)menu designicon designscreen designinformation display

Icon design

Good icon design is difficultMeaning of icons is cultural and context sensitiveSome tips: always draw on existing traditions or standardsconcrete objects or things are easier to represent than actionsFrom clip art, what do these mean to you?

Screen design

Two aspects:How to split across screens moving around within and between screenshow much interaction per screen?Individual screen designwhite space: balance between enough information/interaction and claritygrouping items together: separation with boxes? lines? colors?

Screen design: individual screen design

Draw user attention to salient point, e.g. colour, motion, boxingAnimation is very powerful but can be distractingGood organization helps: grouping, physical proximityTrade off between sparse population and overcrowding

Principles of Visual interface designAvoid 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.

Organization of Screen ElementsBalanceSymmetryRegularityPredictabilitySequentialityEconomyUnityProportionSimplicityGroupings

BalanceEqual weight of screen elementsLeft to right, top to bottom

BalanceUnstable

BalanceLeft column processed - Right column noted as same

Both columns need to be understood by visual processing system

SymmetryReplicate elements left and right of the center line

SymmetricAsymmetric

RegularityCreate standard and consistent spacing on horizontal and vertical alignment points

RegularityLeft column processed - 2 right columns noted as same

Location & size of each object processed

PredictabilityPut things in predictable locations on the screen

PredictableSpontaneous

PredictabilityUser expects title & menu bar on top of screen

Visual scene needs to be completely processed - objects not in expected placesIconFile Edit View Insert Window HelpKung FooSearch for MoviesCancelOKEnter Keywords:GrasshopperOld blind guyIconFile Edit View Insert Window HelpKung FooSearch for MoviesCancelOKEnter Keywords:GrasshopperOld blind guy

SequentialityGuide the eye through the task in an obvious wayThe Eye is attracted to:bright elements over less brightIsolated elements over groupedgraphics before textcolor before monochromesaturated vs. less saturated colorsdark areas before lightbig vs. small elementsunusual shapes over usual ones

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

SequentialRandomMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancelMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancel

EconomyUse as few styles, fonts, colors, display techniques, dialog styles, etc., as possible

EconomicalBusyMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancelMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancel

UnityMake items appear as a unified whole (for visual coherence)Use similar shapes, sizes, or colorsLeave less space between screen elements than at the margin of the screen

UnityFragmentation

ProportionCreate groupings of data or text by using aesthetically pleasing proportions

Pleasing Proportions

SimplicityMinimize the number of aligned pointsUse only a few columns to display screen elementsCombine elements to minimize the number of screen objectsWithin limits of clarity

SimplicityOnly four alignments need to be processed

A total of nine alignments need to be processedName:Address:City:State:Zip:Dues:Pubs:Total:OKCancelMembership FormMembership FormName:Address:City:State:Zip:Pubs:Total:OKCancel

SimpleComplexSize:Uniformity:Height:Width:Preserve Proportions % of original % of originalSize::Preserve Proportions % of original height % of original width

GroupingsUse visual arrangements to provide functional groupings of screen elementsAlign elements in a groupEvenly space elements in a groupProvide separation between groupsUse additional group elements sparinglycolor & borders add complexity

Similar elements aligned verticallyVertical distance between similar objects smallSimple Grouping

Boxes add additional complexity to formSpatial arrangement adequateMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancelBoxed Grouping

Background GroupingMembership FormName:Address:City:State:Zip:Dues:Pubs:Total:OKCancelColor adds additional visual complexitySpatial arrangement adequate

Alignment Grids and the Users Logical PathAlign 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.

Aligned grid layout

Screen-based Controls Widgetselements of screen displaysinteraction toolkitsready-made interaction objectspredefined behaviorscustomizable properties

Functions of Widgets Selecting options and commandsEntering and editing data valuesDisplaying data

Kinds of WidgetsButtonsText entry/read-onlySelectionCombination entry/selectionSpecialized or customPresentation

Design issuesLabels and graphicsLayout and organizationActivation

Labels and GraphicsUse labels and captionsUse standard names when appropriateUse regular system fontClearly tie the text to the controlMaintain consistent heights and widths Use common shapes (mostly rectangles)Pick icons that map to the actionsSupplement icons with text descriptions

Layout and OrganizationProvide adequate spacing Limit the number of controls on one screenKeep related controls togetherUse visual enclosure of groups where appropriate

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.

Aligning radio buttons

This :Not this:

ActivationProvide keyboard equivalentsControl activationMovement among controls within a screenProvide feedback for actions Gray out unavailable choices

ButtonsInitiates an actionto activate a command (an alternate to menu choice or command line entry). to display another window or menu selectionAlways visibleprovides convenient access to frequently-used commandsstandard shapes and screen location for similar commands.Logical organization

ButtonsTypesCommand buttons -- text as labels Bar buttons (menu buttons) -- graphics and/or text as labelsRadio buttons

NextMicrosofts Button Types

Which one is better?Plan Choice:LimitedBasicSuperiorPremiumPlan Choice:LimitedBasicSuperiorPremiumLimitedBasicSuperiorPremiumPlan Choice

Button Design IssuesLabelsShapes and GraphicsLocation and layout OrganizationActivation

Buttons -- labelsUse standard button labels when availableProvide meaningful action descriptionUse regular system fontunless for some special purposesCenter the label textProvide consistency across all screens

Buttons --shape and graphicsUse rectangular shape whatever possibleMaintain consistent button heights and widthsDesign graphics/icons that have natural mapping to the actionsEnhanced graphics with text description

Buttons -- OrganizationMaintain consistency in button locations across screens and windowsprovide adequate spacing between buttons and other screen controlsRestrict the number of buttons on one screenFollow standardsKeep related buttons together

Buttons -- ActivationConsider different actions formouse enter/exit .. mouse down/up/Consider keyboard equivalents for actionsProvide feedback for actions highlight the button when the button is selectedGray out unavailable choices.

Text Entry/Read-Only ControlsText boxesEditable/read-only (fields vs. labels)single line/multiple linesfixed size/resizablefixed length/variable lengthsvisual box/non-visual boxscrollable /non-scrollable Properties background/foreground colorssizes/fonts/styles of textalignments

Text Box DesignProvide descriptive captionLogical arrangement of multiple fieldsConsider the cursor movement from one field to another.Provide large enough boxes for fixed-length dataSelect reasonable fonts/sizes/colorsDesign highlight to attract attention

Selection ControlsPresent all options or choices on the screenRadio ButtonsCheck BoxesPalettesList BoxesCombo BoxesDrop-Down/Pop-UpSingle Selection/Multiple Selection?

Selection DesignChoice DescriptionMeaningful and clear description for the value or effects of the choiceUse single line of text whenever possibleOrganizationMeaningful order of choicesConsider adding a enclosure boxActivationProvide visual feedbackProvide default values

List Box or Combo Box?List boxunlimited number of choicespossible multiple choicesconsumes screen spacecan be set to different sizeeasy to see the choices

Combo boxunlimited number of choiceshighlight the selectionconserves screen spaceExtra step to display all the choices

More Selection ControlsSpin Boxes

Attached Combo Boxes

0.5Left Margin:Font Style:RegularItalicBoldBold ItalicRegular

Other ControlsScroll BarsSlidersToggle Switches Tab pagesContain tabbed divider pages

Presentation ControlsProvide additional information to screen elementsTooltips a small popup window attached to an objectshows only when the mouse moves over the objectStatic Text Fields -- labelsGroup BoxesCombined controls in one boxProgress Indicators

Message Design

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