HCI Task Models

Approaches to task analysis

• Task decomposition
• splitting task into (ordered) subtasks
• Knowledge based techniques
• what the uer knows about the task and how it is organised
• Entity/object based analysis
• relationship between objects, actions and the people who perform them
• Lots of different notations/techniques

Task analysis is a method to analyze people's jobs

• What people do
• What things they work with 
• What they must know

Knowledge Based Analyses

• Focus on objects
• actions performed

Taxonomies

• represent levels of abstraction

Entity-relationship techniques

• Focus on objects, actions and their relationships
• Similar to OO analysis but includes non-computer entities
• emphasises domain understanding not implementation

Uses - Manuals and documentation

• Conceptual Manual
• from good knowledge or entity-relations based analysis
• good for open ended tasks
• Procedural 'how to do it' manual
• form HTA description
• good for novices
• assumes all tasks known