HCC 831 User Interface Design and Evaluation

What is Usability?

The effectiveness and efficiency of the user interface and the user’s reaction to that interface.

What is Usability? ISO. "Ergonomic requirements for office work with visual display terminals (VDTs) -- Part 11: Guidance on usability", (ISO :1998).

What is Usability? Must measure: Must measure: 1. Effectiveness 2. Efficiency 3. User’s Reaction Easier said than done! Easier said than done!

Usability Warnings 1. Interface designed by software people, not interface people. 2. It was developed by strict top- down, functional decomposition. (Emphasis on software function) 3. It was not developed to meet written, measurable usability specifications.

Usability Warnings 4. It was not prototyped as it was being developed. 5. It was not developed by means of an iterative refinement process. 6. It was not empirically evaluated.

Usability Goal Promote communication between humans and computers. Promote communication between humans and computers. Make this communication doable or easy. (User Friendly) Make this communication doable or easy. (User Friendly)

Human Computer Interaction (HCI or CHI) HCI HCI This is what occurs when a human interacts with a computer or some other machine. This is what occurs when a human interacts with a computer or some other machine.

HCI Includes Interface hardware and Software Interface hardware and Software Interface Tools Interface Tools User Modeling User Modeling System Modeling System Modeling

HCI Includes Cognitive and Behavioral Science Cognitive and Behavioral Science Human Factors Human Factors Empirical Studies Empirical Studies Methodology Methodology Techniques and Guidelines Techniques and Guidelines

Interaction vs. Interface Design

Interaction Design Behavioral Domain Behavioral Domain Interaction development is the design of the look, feel and input/output responses of the human interface. Interaction development is the design of the look, feel and input/output responses of the human interface.

Interface Design Constructional Domain Constructional Domain Interface development focuses on the software being used to implement the interactions. Interface development focuses on the software being used to implement the interactions.

Interaction and Interface Interface Design follows Interaction Design. Interface Design follows Interaction Design. Both are necessary. Both are necessary. Tendency is to focus on Interface Design, Software Engineers. Tendency is to focus on Interface Design, Software Engineers.