This chapter presents the following content: Usability, usability design process, use scenario development, UI structure/flow of control, interface standards design, interface design prototyping, creating a UI prototype, heuristic evaluation, interface/dialogue design,. | Software Construction Lecture 15 USABILITY and USER INTERFACE DESIGN (CONTD ) Usability What is Usability? Ease of learning Ease of use Ease of remembering Subjective satisfaction Efficiency of use Effectiveness of use Usability Design Process Use Scenario Development You already know about use cases Use scenarios are just a single thread through a use case – much simpler! UI Structure/Flow of Control UI Structure/Flow of Control This matters much less than it used to. Why? What can you do about it? Users often jump right in to the middle of a web-site (via search). This means even more opportunities to be “lost in space”. What to do? Always make it clear: what the web-site is for, who you are, how to go to the home page. Interface Standards Design The interface standards are the basic design elements that are common across the screens, forms, and reports within the system. Example What do you think of this? | Software Construction Lecture 15 USABILITY and USER INTERFACE DESIGN (CONTD ) Usability What is Usability? Ease of learning Ease of use Ease of remembering Subjective satisfaction Efficiency of use Effectiveness of use Usability Design Process Use Scenario Development You already know about use cases Use scenarios are just a single thread through a use case – much simpler! UI Structure/Flow of Control UI Structure/Flow of Control This matters much less than it used to. Why? What can you do about it? Users often jump right in to the middle of a web-site (via search). This means even more opportunities to be “lost in space”. What to do? Always make it clear: what the web-site is for, who you are, how to go to the home page. Interface Standards Design The interface standards are the basic design elements that are common across the screens, forms, and reports within the system. Example What do you think of this? Interface Design Prototyping Storyboard HTML Prototype Language Prototype Interface Evaluation Heuristic Walkthrough Interactive Formal Usability Testing Creating a UI Prototype Low-fidelity prototypes are good! . Paper prototype Visio/HTML/PPT/ prototype Example Heuristic Evaluation Set of guidelines for creating usable GUIs See: for a good example of a set of guidelines as a checklist. Interface/Dialogue Design The team needs to worry about: Layout (of buttons, text, table data, ) Structuring data entry (tab order) Controlling data input (validation and format controls) Feedback (prompting, status, warning, and error messages) Dialogue sequencing 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 GUI Design .
