Designing Systems for People User Types Task Analysis Course 9, CMC, 28/10/03

28/10/03HC92 Design Effective Interface Basic questions: Who is the user? What is the task? What is the environment in which the system will operate?

28/10/03HC93 Role Interface Provides cushioning buffer between user and system Provides system’s half of a conversation with user Identifies system’s functionality Conveys current state of activity Provides clues for organizing user task

28/10/03HC94 User Types novice users knowledgeable intermittent users expert/frequent users

28/10/03HC95 Knowledge Chunking Logging on Process Expert’s view input username input password First user’s view press key to activate screen press return to display menu input menu choice press return input username press return input password press return wait for welcome message

28/10/03HC96 Guidelines for Novice Users Initiatives come from computer Required input brief System’s actions match user expectation System uses knowledge of the world (metaphor) System messages clear and unequivocal Small set of options User control of pace of interaction Decision making in response to specific request Help always available Sufficient feedback

28/10/03HC97 Controls suggesting Appropriate Behaviour 1

28/10/03HC98 Controls suggesting Appropriate Behaviour 2

28/10/03HC99 Examination of User’s Task What does user do to perform task? What information does user need to perform task? What affects task performance? What causes error in task performance? What are good / bad features in present system? What skills are required to perform task? How are these skills acquired? How are these skills maintained? Transforrmations of task environment: environmental factors; external procedures; time constraints

28/10/03HC910 Task Analysis: tea (Dix, 1994)

28/10/03HC911 The Notion of Task in HCI Draper, 1993 Problematic notion: a task is not the same thing to all people in all circumstances (e.g. preparing a business letter) Plea in favour of prototyping cycle for task analysis: task analysis -> design product -> build prototype -> evaluate