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

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

Basic activities of interaction design projects 1.Identify needs and establish user requirements 2.Develop alternative designs 3.Conceptual designs/model Physical designs/product detail 4.Build interactive prototypes 5.Evaluation

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.

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

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).

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

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.

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

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

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

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.

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

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.

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)

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

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

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?

Next individual/group assignment tentative 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.