1. Principles to Support Usability - Robustness Group 3 Topic 2 IM2044 Usability Engineering Student ID: 0422902 0409543

2. What is it? The level of support provided the user in determining successful achievement and assessment of goal directed behavior. How easy is it to evaluate whether the goals have been achieved?

3. 4 Main principles are: Observability Browsability; defaults; reachability; persistence; Operation visibility Ability of user to evaluate the internal state of the system from its perceivable representation

4. 4 Main principles are: Recoverability Reachability; forward/backward recovery; Commensurate effort Ability of user to take corrective action once an error has been recognized

5. 4 Main principles are: Responsiveness Stability How the user perceives the rate of communication with the system

6. 4 Main principles are: Task conformance Task completeness; task adequacy Degree to which system services support all of the user's tasks

7. Examples using an Internet browser DefaultsFile saves PersistentAlerts ReachabilityNavigation Netscape