Interface Types and Models

1. Interface Types and Models Dr. Dania Bilal IS 588 Spring 2008

2. Interaction design • Focuses on designing and building interactive products • How to accomplish User-Centered Design • User rather than system concerns to guide the development process • Requires the work of a team

3. Basic activities of interaction design projects • Identify needs and establish user requirements • Develop alternative designs • Conceptual designs/model • Physical designs/product detail • Build interactive prototypes • Evaluation

4. Life cycle models • Show how activities fit together • Limited by resources • Provide a framework for managing projects • Simple model • See Text, fig. 9.7, p. 448.

5. Life cycle models • Software engineering • Waterfall • Spiral • Rapid Application Development (RAD) • HCI • Star Lifecycle • Usability Engineering

6. Waterfall lifecycle • First generally used life cycle model for software development • Originally proposed in the 1970’s • Linear model • 5 stages • User involvement not built into the model (see fig. 9.8, p. 450).

7. Waterfall model • Some level of iteration • Requirements are frozen while design and implementation are completed • Problem • Iteration around each stage and previous but not all over • No account for change over time • Lacks an explicit role for user involvement

8. Spiral lifecycle • Created by Barry Boehm in 1988 • Integrate risk analysis & prototyping into the model • Results in the inclusion of iterative testing of alternatives appropriate to each given stage • See fig., 9.9, p. 451.

9. Rapid Application Development (RAD) • Developed in the 1990’s in response to pressure to include user focus • Goal: minimize the risk of changing the requirements over time • Non-linear • Iterative process • See fig. 9.10, p. 452

10. Key features of RAD projects • Time boxes • Time limited cycles (about 6 months) • Breaks a large project into smaller projects • Deliver incrementally • Enhance flexibility • Joint Application Development (JAD) “workshops” • Users and developers thrash out requirements • stakeholder groups are involved in design

11. RAD phases • Project initiation • JAD workshops • Design and build (iterative) • Evaluation of final system • Review implementation

12. Star lifecycle • Developed from research on interface designers • Distinguishes analytical & synthetic modes of working • Model suggests activity can begin at any point IF it flows through evaluation • See fig. 9.15, p. 459.

13. Usability engineering lifecycle • Beginnings: • Whiteside, Bennett & Holtzblatt at DEC in 1988 • Nielsen at Bellcore 1992 • Deborah Mayhew’s textbook (1999) • Detailed specification for how to do usability engineering • How to integrate usability testing into the product lifecycle

14. Usability engineering basics • Set usability goals as part of system specification • Goals must be quantitative • Measures may include • Behaviors • Time to complete task, % task completion, number/percent errors, number of commands, etc. • Attitudes • User preference, user satisfaction, etc.

15. Requirements: A definition • “Statements about an intended product that specifies what it should do or how it should perform” • Types • Functional • Non-functional • Serve as constraints • Include: data requirements, environmental constraints (physical, social, organizational and technical)

16. Who are your users? • Stakeholders • Types of users (Eason, 1987) • Primary • Frequent, hands-on • Secondary • Occasional users • Tertiary • Affected by system introduction • May have purchase power over system

17. Finding out about your users • Chapters 8,7,10 • Data gathering methods • Choosing among methods • Data interpretation and analysis • Tasks description • Task analysis

18. Group Class Activity • You are developing a digital repository for an agency (select an information agency or a library of your choice) • The depository will include digitizing a specific collection and designing a system to provide access to the collection. • How will you begin and what model will you use?

19. Next individual/group assignmenttentative description • Think of a product you want to design. • Product should be of common interest to you and the group you will work with • What do you want the product to do for you? • Find 5 potential users of the product and interview them about the product (what are their requirements?) • Write a list of requirements based on the information you gathered. • Meet with the team, discuss the requirements you collected, refine the requirements and generate a comprehensive list of these requirements (from all team members). • Identify and describe the requirements that are feasible for feeding into the interaction design of the product and justify why. • Find similar products and evaluate their design vis-à-vis the requirements you collected. • Sketch some initial design for the product. • Sketch alternative design for the product. • Evaluate the two designs with “real users” based on usability criteria and user experience goals. • Reiterate the design based on the results of the usability criteria and user experience goals • Write a final report.