Task analysis-> statement of requirements for a system. When creating a “hierarchy with attendant rules” (p.514) use information from “direct observation, expert opinion (domain expert), documentation.” Task decomposition is concerned with breaking down tasks into subtasks and what order and how often they should be performed. In contrast, knowledge-based analysis includes a special focus on the objects and actions involved with the tasks being performed. The third technique discussed is entity-relationship modeling and it aims to detail the relationships between the objects and actions of a task. Agent-> action (or spontaneous event)-> patient. Messages or communication is also an important factor in ERM, as well as the roles of the various agents involved.
Analysis of notes taken from observation, interviews, and manuals/ rule books/ etc. begins with making lists of basic objects and actions (nouns and verbs) while keeping context in mind. Next, make hierarchies and sort the objects and actions by some attribute or attributes. Card sorting and ranking are often employed here. Overall, task analysis can be used to create manuals, course materials, help users learn new systems by understanding the differences between old and new systems, to design a completely new system, and to design interfaces.