Our world is complex. Sometimes the best approach to tackling this complexity is to break it down into smaller pieces. That is the job of Hierarchical Task Analysis - a structured approach for breaking down complex processes so we can gather and document information about how people carry out tasks. No matter how complex your job may feel or how difficult an activity may seem, you can use hierarchical task analysis to break these complicated and complex tasks into simple descriptions of how these task can combine to achieve your goal.
Hierarchical task analysis starts by identifying the steps (called tasks) needed to accomplish a goal. Plans describe how the tasks fit together. Tasks can be further broken down into smaller and smaller sub-tasks as far as necessary. These tasks, sub-tasks and plans are then arranged in a hierarchy in order to represent the relationship between the different steps making up the overall activity. We use the terms goal and task interchangeably. For most practical purposes, this distinction is not important.
Once the structure of the tasks is documented, analysis proceeds by collecting information about the properties of the tasks, the mission/job conditions, standards, performance steps, required skills and knowledge, safety and environmental factors, references, equipment, and job performance measures.
Task analysis is the first step in taking a systemic approach to design. Task analysis can focus on both what actually happens in the workplace now, or can be used as a tool to specify the design of a new system. Task analysis provides a detailed description of how goals are accomplished so that designers can provide means of enhancing human performance.