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Chapter 12 Designing Interfaces and

Dialogues

Modern Systems Analysisand Design

Fourth Edition

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Interface/Dialogue Design

– Layout (of widgets, text, and table data)

– Structuring data entry (tab order)

– Controlling data input (validation and format controls)

– Feedback (prompting, status, warning, and error messages)

– Dialogue sequencing

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A typical interface/dialogue design specification:

Similar to form design, but includes multiple forms and dialogue sequence specifications

Deliverables and Outcomes

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Interface Methods

• Interface: the method by which a user interacts with the information system

• Common interaction methods– Command line– Menu– Form– Object-based– Natural language

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Guidelines for Menu Design

• Wording: meaningful titles, clear command verbs, mixed upper/lower case

• Organization: consistent organizing principle

• Length: all choices fit within screen length• Selection: consistent, clear and easy

selection methods• Highlighting: only for selected options or

unavailable options

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Good Menu Design

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Form Interaction

• Measures of an effective design:– Self-explanatory title and field headings– Fields organized into logical groupings– Distinctive boundaries– Default values– Displays appropriate field lengths– Minimizes the need to scroll windows

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Designing Interfaces

• Use standard formats similar to paper-based forms and reports

• Left-to-right, top-to-bottom navigation• Flexibility and consistency:

– Free movement between fields– No permanent data storage until the user

requests – Each key and command assigned to one

function

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Structuring Data EntryEntry Never require data that are already online or

that can be computed

Defaults Always provide default values when appropriate

Units Make clear the type of data units requested for entry

Replacement Use character replacement when appropriate

Captioning Always place a caption adjacent to fields

Format Provide formatting examples

Justify Automatically justify data entries

Help Provide context-sensitive help when appropriate

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Feedback Messages

• Status information: keep user informed of what’s going on, helpful when user has to wait for response

• Prompting cues: tell user when input is needed, and how to provide the input

• Warning or Error: inform user that something is wrong, either with data entry or system operation

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Providing Help

• Place yourself in user’s place when designing help

• Guidelines:– Simplicity

• Help messages should be short and to the point

– Organize• Information in help messages should be easily

absorbed by users

– Show• It is useful to explicitly show users how to perform

an operation

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What is a Dialogue?

• A sequence of interactions between the system and a user

• Dialogue design involves:– Designing a dialogue sequence– Building a prototype– Assessing usability

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Guidelines for Dialogue Design

• Consistency

• Shortcuts and Sequence

• Feedback

• Closure

• Error Handling

• Reversal

• Control

• Ease

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Dialogue DiagrammingA formal method for designing and representing human-computer dialogues using box and line diagrams

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Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.

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