5 Place the User in Control Define interaction modes in a way that does not force a user into unnecessary or undesired actionsProvide for flexible interactionAllow user interaction to be interruptible and undoableStreamline interaction as skill levels advance and allow the interaction to be customizedHide technical internals from the casual userDesign for direct interaction with objects that appear on the screen
7 Reduce the User’s Memory Load Reduce demand on short-term memoryEstablish meaningful defaultsDefine shortcuts that are intuitiveThe visual layout of the interface should be based on a real world metaphorDisclose information in a progressive fashion
9 Make the Interface Consistent Allow the user to put the current task into a meaningful contextMaintain consistency across a family of applicationsIf past interactive models have created user expectations, do not make changes unless there is a compelling reason to do so
11 Interface Analysis and Design Models Four different models come into play:User modelDesign modelMental model / system perceptionImplementation model
12 The Process User, task, and environment analysis and modeling Interface designInterface construction (implementation)Interface validation
13 User AnalysisAre users trained professionals, technicians, or workers?What level of formal education average user has?Are users capable of self-learning or require classroom training?What is the age range of the user community?Will users be represented by one gender?Do users work office hours or until work is done?What is the primary spoken language among users?What are the consequences of making a mistake?
14 User Analysis User interviews Sales input Marketing input Support input
15 Task Analysis and Modeling Goal of task analysis is to answer the following questions:What work will the user perform?What tasks and subtasks will be performed?What specific problem domain objects will the user manipulate?What is the sequence of tasks (workflow)?What is the hierarchy of tasks?
16 Task Analysis and Modeling Use-casesTask elaborationObject elaborationWorkflow analysisHierarchical representation
17 Analysis of Display Content Questions that need to be answered:Are different types of data are assigned to different location on screen?Can user customize screen location for content?How is a large report partitioned for ease of understanding?Will graphical output be scaled to fit within display?How error messages will be presented?
18 Analysis of the Work Environment Will system be placed in a user-friendly location?Will two or more people share information?Is proper lighting present?Keyboard / mouse access?
19 Interface Design Steps Using information developed during interface analysis, define interface objects and actionsDefine events (user actions) that will cause the state of the user interface to changeDepict each interface state and it will actually look to the end-userIndicate how the user interprets the state of the system from information provided through the interface
20 Design Issues Response time Help facilities Error handling Menu and command labelingApplication accessibilityInternationalization