yonglei tao school of computing & info systems gvsu ch 7 design guidelines
TRANSCRIPT
Yonglei TaoYonglei TaoSchool of Computing & Info School of Computing & Info
SystemsSystemsGVSUGVSU
Ch 7 Design Guidelines
GuidelinesGuidelines
1. Help the user build and use a workable mental model
2. Minimize modal interaction3. Reduce the cognitive workload
of the user4. Let the user be in charge
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Guideline 1Guideline 1Help the user build and use a
workable mental model◦Consistent with the intended tasks◦Consistent representations◦Use concrete and familiar ideas for
metaphors◦Use the user’s language◦Guide new users through normal and
reasonable patterns of usage◦Provide feedback
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ConsistencyConsistencyFunctional consistency
◦ The same action should have the same result regardless of the mode the application is in
Consistent appearance/behavior◦ comparable operations should be
expressed in the same wayConsistency within and among
applications
BenefitsBenefitsPredictable in appearance and
behavior throughout the application’s display of information, manner of manipulating information, and methods of navigation
Facilitating user’s learning◦ Result in great productivity and efficiency
Reusable design◦ Increase productivity and product quality
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Consistent Appearance Consistent Appearance and Behaviorand Behavior
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User FamiliarityUser Familiarity Do not force users to adapt to an
interface just because it is convenient to implement◦ Use terms and concepts from the
experience of users◦ Hide the underlying implementation of
interfaces (such as files and data structures)
Consistency with the real world◦ base interface design on a real-world
metaphor
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Minimal SurpriseMinimal Surprise Users get irritated when a system
behaves in an unexpected way Need to ensure that comparable
actions have comparable effects Users become confused or panic if no
response to their actions from the system
Guideline 2Guideline 2Minimize modal interactionVisibility
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VisibilityVisibilityMaking the user aware of the system’s
components and processes, including all possible functionality and feedback from user actions.◦ Reduce memory load
Recognition/Recall◦ the principle of visibility is based on the fact that we
are better at recognition than we are at recall
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Show everything at once, and the result is
chaos.
Don’t show everything, and then stuff gets lost.
(Norman, 1998, 74)
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Can You Tell between Edit Can You Tell between Edit and Preview ?and Preview ?
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Excel ModeExcel Mode
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Excel Mode (Cont.)Excel Mode (Cont.)
Mode of a Mobile Phone Mode of a Mobile Phone
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Guideline 3Guideline 3Reduce the cognitive workload of
the user◦Present options clearly and explicitly
without multiple, reasonable interpretations
◦Reduce the number of cognitive transformations or translations from the interface to the user’s mental model
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ClarityClarity
Visual clarity◦ graphical representations can be clearly
identified Conceptual clarity
◦ behavior of control is clear◦ the metaphor is easily recognized
Linguistic clarity◦ meaning of labels and static text clarify
contents
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Visual ClarityVisual Clarity
Reduce the User’s Info Reduce the User’s Info LoadLoadUsers should not be required to
remember information from one screen for use on another screen.
Tasks should be arranged such that completion occurs with few actions, minimizing the chance of forgetting to perform a step.
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Common TechniquesCommon TechniquesRecognition, rather than recallAllow users to perform actions by
choosing alternatives presented on the screen, as opposed to remember particular command or name
Build on user's frame of reference Labels and common formats should be
provided for users
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Techniques - SimplicityTechniques - Simplicity
Simple things are easy to understand and, therefore, easy to learn and remember
◦ 80/20 Rule - 80% of an application’s usage involves 20% of its functionality
◦ Combines the conflicting needs of finding the optimal solution that satisfies all the requirements
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ExampleExample
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ExampleExample
Techniques - Progressive Disclosure
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ConstraintsConstraints
Limiting the actions that can be performed in a particular design
Controls the design’s simplicity
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Guideline 4Guideline 4Let the user be in charge
◦Allow users to accomplish tasks directly
◦Allow users to try again◦Provide appropriate feedback to
users
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Make the Interface Make the Interface ForgivingForgiving
Users inevitably make mistakes when using a system
Users should be able to explore without fear of causing an irreversible mistake◦ Prevention◦ Toleration◦ Recovery
Common TechniquesCommon TechniquesAllow the user to select instead of
typingDisable improper menu items or
buttons by graying the option Confirm destructive actions or actions
that result in an unexpected loss of user info (such as Cancel, OK command buttons)
Provide undo and redo facilities
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