TRAINING PACKAGE The User Action Framework Reliability Study July 1999

What is the UAF? q Conceptual framework of usability concepts and issues q Formed by combining a user interaction cycle with a knowledge base of usability concepts and issues q UAF provides a basis for: organizing, discussing, classifying, and reporting usability problems q Is the basis for a set of usability support methods and tools: l Usability Problem Design Guide l Usability Problem Inspector l Usability Problem Classifier l Usability Problem Database

The Interaction Cycle q Helps organize usability issues and concepts q Adapted from Norman (1986) q A picture of how interaction happens q Based on user actions (cognitive and physical)

Flow of Interaction Cycle

About Planning q Planning breaks down into two important parts: l High-level planning l Translation Goal:Always work/problem domain (e.g., produce business letter) Task: Intention: Action plan: Planning tasks to be done using computer (e.g., formatting the page) Planning intentions to be done using computer (e.g., user intends to set left margin) Plan for physical actions to be done on computer (e.g., decide to drag margin marker in MS Word)

About High-Level Planning q Where user decides what to do q Identify work needs and establish goals, tasks, and intentions q Example areas: l Goal decomposition (what to do next, understanding sequence of tasks) l User’s model of system (understanding overall system model/metaphor, expectations)

About Translation q Where user figures out how to do it (“getting started”) q Translating from the language of the problem domain to the language of actions upon user interface objects q Example areas: l Existence of a way (missing feature) l Cognitive affordance to show the way (visual cues) l Efficient way to “do it” (accommodating different user classes, shortcuts) l Help user do right thing (error avoidance)

About Physical Actions q All user inputs to operate controls and manipulate objects within the user interface (e.g., clicking, typing, dragging) q Example areas: l Perceiving affordances l Manipulating affordances l Physical control l Fitts' law l Manual dexterity l Physical accessibility and disability

About Outcome q Internal state change within system due to the user action q User normally infers the outcome based on system response, through feedback q Example areas: l System automation l Locus of control l System is presumptuous about what the user wanted l System errors

About Assessment q Evaluate what happened and the favorability or desirability of the outcome q How feedback is perceived, understood, and used to assess the outcome of a user action q Example areas: l Existence of feedback (necessary but missing, unnecessary, not expected) l Appearance of feedback (legibility, noticeability) l How well feedback is expressed (clarity, completeness, efficient)

Classifying Problems q Finding the correct entry point in the Interaction Cycle for a usability issue is based on asking: l How the user and task performance are affected by the design during interaction q Classification of a usability situation begins by associating it with the appropriate cognitive or physical user action in the Interaction Cycle q Then the usability situation is classified within the taxonomy underneath the Interaction Cycle by systematically matching usability attributes that pair up effects of a design feature on the user with usability problem causes in the interaction design

Cause and Effect q Locate the Cause-in-Design (essence of the problem) q Select one or more Effect-on-User attributes q Example: Hard to read feedback message Cause-in-Design Assessment Perceptual Issues Presentation Legibility    Effect-on-User 4Slowed down 4Difficulty with perceiving

Key Terms q Cognitive affordance (visual cues to see a button) l Aids for knowing and understanding l Aids to show the way q Physical affordance (a button that can be “clicked”) l Aids for doing q Example l A chair provides both. Physical affordance of a chair allows sitting on it. Cognitive affordance of a chair lets user see that it is something to sit on q Effective affordances support the users' ability to plan physical actions to carry out intentions