Ch 3 Usability page 1CS 368 Usability Models the authors compare three usability models and introduce their own “the extent to which a product can be used to achieve specific goals with effectiveness, efficiency and satisfaction.” usability is one measure of success within software engineering that might also include: functionality, cost, maintainability. each characteristic must be measurable. Measures can be quantitative or qualitative and subjective or objective. Opinions of experts can also be used. collectively, used to measure the usability of an existing system or iteratively during the development of a new system additional areas of usability documentation installation support maintenance

Ch 3 Usability page 2CS 368 User Interface Characteristics Ease of learning - amount of time to become proficient Ease of use - efficiency after becoming proficient Ease of relearning - amount of time to learn a second time Task match - the extent to which the system features match the user needs Flexibility - ability to support unanticipated usage patterns Satisfaction - from the user’s perspective

Ch 3 Usability page 3CS 368 Key Factors that Influence Usability Place usability into context Tasks frequency - how often is the task performed rigidness - how many options / alternatives available to complete the task situational - security, collaboration, environment User expertise - novice, occasional or expert (power) motivation - high or low

Ch 3 Usability page 4CS 368 Group Activity Identify appropriate characteristics and measurements for using Banner to register for Winter courses. Identify key factors for tasks and users Identify standard tasks, representative tasks, benchmark tasks.