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Interface DesignInterface Design

Easy to use?Easy to use?

Easy to understand?Easy to understand?

Easy to learn?Easy to learn?

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Interface DesignInterface Design

lack of consistencylack of consistencytoo much too much memorizationmemorizationno guidance / helpno guidance / helpno context sensitivityno context sensitivitypoor responsepoor responseArcane/unfriendlyArcane/unfriendly

Any others?Any others?Rank?Rank?

Typical Design ErrorsTypical Design Errors

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12.1 Golden 12.1 Golden RulesRules

Place the user in controlPlace the user in control Reduce the user’s memory loadReduce the user’s memory load Make the interface consistentMake the interface consistent

Reasonable?

Quote pg. 357 “a system that reads my mind…knows

what I want to do before I need to do it and makes it very easy for me to get it done…”

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Place the User in ControlPlace the User in ControlDefine interaction modes in a way that does not force a user into Define interaction modes in a way that does not force a user into

unnecessary or undesired actions. unnecessary or undesired actions.

Provide for flexible interaction. Provide for flexible interaction.

Allow user interaction to be interruptible and undoable. Allow user interaction to be interruptible and undoable.

Streamline interaction as skill levels advance and allow the Streamline interaction as skill levels advance and allow the interaction to be customized. interaction to be customized.

Hide technical internals from the casual user. Hide technical internals from the casual user.

Design for direct interaction with objects that appear on the Design for direct interaction with objects that appear on the screen.screen.

What are some additional design principles that “place the user in What are some additional design principles that “place the user in control”?control”?

Why on the second point?Why on the second point?

Why just the casual user?Why just the casual user?

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Reduce the User’s Memory LoadReduce the User’s Memory Load

Reduce demand on short-term memory. Reduce demand on short-term memory.

Establish meaningful defaults. Establish meaningful defaults.

Define shortcuts that are intuitive. Define shortcuts that are intuitive.

The visual layout of the interface should be based on a real world The visual layout of the interface should be based on a real world metaphor. metaphor.

Disclose information in a progressive fashion.Disclose information in a progressive fashion.

Why?Why?

What does the last point mean?What does the last point mean?

What are some additional design principles that “reduce the user’s memory load”? What are some additional design principles that “reduce the user’s memory load”?

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Make the Interface ConsistentMake the Interface Consistent

Allow the user to put the current task into a meaningful Allow the user to put the current task into a meaningful context. context.

Maintain consistency across a family of applications. Maintain consistency across a family of applications.

If past interactive models have created user expectations, If past interactive models have created user expectations, do not make changes unless there is a compelling reason do not make changes unless there is a compelling reason to do so. to do so.

What are some additional design principles that “make the interface What are some additional design principles that “make the interface consistent”?consistent”?

Usability

Page 361 “What do users want anyway?” Easy to learn and helpful “…interface fits the needs of the people who will

be using it.” How to determine? – assessment/testing Measurable benefits

increased sales and customer satisfaction competitive advantage – examples? reduced cost – examples?

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12.2 User Interface Analysis and 12.2 User Interface Analysis and DesignDesign

User modelUser model — a profile of all end users of — a profile of all end users of the systemthe system

Design modelDesign model — a design realization of the — a design realization of the user modeluser model

Mental model (system perception)Mental model (system perception) — the — the user’s mental image of what the interface isuser’s mental image of what the interface is

Implementation modelImplementation model — the interface — the interface “look and feel” coupled with supporting “look and feel” coupled with supporting information that describe interface syntax information that describe interface syntax and semanticsand semantics

What is the role of designer/engineer?What is the role of designer/engineer?

One/some of the above more important?One/some of the above more important?

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UI Analysis and Design UI Analysis and Design ProcessProcess

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12.3 Interface 12.3 Interface AnalysisAnalysis

Interface analysis means understanding Interface analysis means understanding (1) the people (end-users) who will interact with the (1) the people (end-users) who will interact with the

system through the interface;system through the interface; (2) the tasks that end-users must perform to do their (2) the tasks that end-users must perform to do their

work, work, (3) the content that is presented as part of the interface(3) the content that is presented as part of the interface (4) the environment in which these tasks will be (4) the environment in which these tasks will be

conductedconducted.

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User AnalysisUser Analysis Are users trained professionals, technician, clerical, or manufacturing workers?Are users trained professionals, technician, clerical, or manufacturing workers? What level of formal education does the average user have?What level of formal education does the average user have? Are the users capable of learning from written materials or have they expressed Are the users capable of learning from written materials or have they expressed

a desire for classroom training?a desire for classroom training? Are users expert typists or keyboard phobic?Are users expert typists or keyboard phobic? What is the age range of the user community?What is the age range of the user community? Will the users be represented predominately by one gender?Will the users be represented predominately by one gender? How are users compensated for the work they perform? (Or how are “you” How are users compensated for the work they perform? (Or how are “you”

compensated?)compensated?) Do users work normal office hours or do they work until the job is done?Do users work normal office hours or do they work until the job is done? Is the software to be an integral part of the work users do or will it be used only Is the software to be an integral part of the work users do or will it be used only

occasionally?occasionally? What is the primary spoken language among users?What is the primary spoken language among users? What are the consequences if a user makes a mistake using the system?What are the consequences if a user makes a mistake using the system? Are users experts in the subject matter that is addressed by the system?Are users experts in the subject matter that is addressed by the system? Do users want to know about the technology the sits behind the interface?Do users want to know about the technology the sits behind the interface?

How do we gather the above information?How do we gather the above information?Issues?Issues?Is there a best way?Is there a best way?

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Task Analysis and ModelingTask Analysis and Modeling Use-casesUse-cases define basic interaction define basic interaction Task elaborationTask elaboration refines interactive tasks refines interactive tasks Object elaborationObject elaboration identifies interface objects identifies interface objects

(classes)(classes) Workflow analysisWorkflow analysis defines how a work process is defines how a work process is

completed when several people (and roles) are completed when several people (and roles) are involvedinvolved

Hierarchical representationHierarchical representation defines a task defines a task hierarchy for each user typehierarchy for each user type

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Swimlane DiagramSwimlane Diagrampatient pharmacist physician

requests that a

prescription be re f illed

no refills remaining

checks patient

records

determines status o f

prescription

refills remaining

refill not allowed

approves refill

ev aluates alte rnativ e

medication

none

rece iv es request to

contact physician

alternative available

checks inv entory fo r

re f ill o r alternative

out of stockrece ives out o f stock

notif ication

rece ives t ime/ date

to p ick up

in stock

picks up prescription

f ills

prescription

Figure 12.2 Swimlane diagram for prescription refill function

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Analysis of Display ContentAnalysis of Display Content Are different types of data assigned to consistent geographic Are different types of data assigned to consistent geographic

locations on the screen (e.g., photos always appear in the locations on the screen (e.g., photos always appear in the upper right hand corner)?upper right hand corner)?

Can the user customize the screen location for content?Can the user customize the screen location for content? Is proper on-screen identification assigned to all content? Is proper on-screen identification assigned to all content? If a large report is to be presented, how should it be If a large report is to be presented, how should it be

partitioned for ease of understanding?partitioned for ease of understanding? Will mechanisms be available for moving directly to summary Will mechanisms be available for moving directly to summary

information for large collections of data.information for large collections of data. Will graphical output be scaled to fit within the bounds of the Will graphical output be scaled to fit within the bounds of the

display device that is used?display device that is used? How will color to be used to enhance understanding?How will color to be used to enhance understanding? How will error messages and warning be presented to the How will error messages and warning be presented to the

user?user? Where will content come from?Where will content come from?Opportunities to customize?Opportunities to customize?

Issues with customization?Issues with customization?If yes, how do we fix?If yes, how do we fix?

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Analysis of the Work Analysis of the Work EnvironmentEnvironment

What are some of the physical characteristics of a What are some of the physical characteristics of a workplace that can affect user interface design? workplace that can affect user interface design?

Are there other characteristics to examine?Are there other characteristics to examine?

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12.4 Interface Design 12.4 Interface Design StepsSteps

1.1. Using information developed during interface Using information developed during interface analysis (SEPA, Section 12.3), analysis (SEPA, Section 12.3), define interface define interface objects and actions (operations).objects and actions (operations).

2.2. Define events (user actions)Define events (user actions) that will cause the that will cause the state of the user interface to change. Model this state of the user interface to change. Model this behavior.behavior.

3.3. Depict each interface stateDepict each interface state as it will actually look to as it will actually look to the end-user.the end-user.

4.4. Indicate how the user interprets the state of the Indicate how the user interprets the state of the systemsystem from information provided through the from information provided through the interface.interface.

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Interface Design PatternsInterface Design Patterns Patterns are available forPatterns are available for

The complete UIThe complete UI Page layoutPage layout Forms and inputForms and input TablesTables Direct data manipulationDirect data manipulation NavigationNavigation SearchingSearching Page elementsPage elements e-Commercee-Commerce

Are these used?Are these used?

Why or why not?Why or why not?

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Design IssuesDesign Issues Response time (length and variability)Response time (length and variability)

One more important?One more important? Help facilities (old way was a colleague or a big paper Help facilities (old way was a colleague or a big paper

manual)manual) What ways do/should we use today?What ways do/should we use today?

Error handlingError handling Best practices?Best practices?

Menu and command labelingMenu and command labeling 1-to-1?; Customizable?; Form? (Alt-something, Function keys, 1-to-1?; Customizable?; Form? (Alt-something, Function keys,

command line) command line) Application accessibilityApplication accessibility

What do we mean?What do we mean? InternationalizationInternationalization

Is this desirable?Is this desirable? Possible?Possible?

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Design Evaluation Design Evaluation CycleCyclepreliminary

design

buildprototype #1

interface

evaluationis studied by

designer

designmodifications

are made

buildprototype # n

interface

userevaluate'sinterface

Interface designis complete