This method was developed at the University of Hull in response to the need to analyze complex tasks; those are generally found in the chemical-processing and power-generation industries (Annett et al., 1971). Hierarchical task analysis (HTA) is a basic technique which is useful for analysis of many cognitive tasks. This method implies, break down of the task under analysis into a hierarchy of goals, operations and plans. Goals may be associated with operation of the device. Operations are the noticeable behaviours or activities which achieve the goals. Plans are choices, decision and planning on behalf of the operator.

In this method, the task is generally described by a task statement, which states the overall goal of the task. This task statement forms the top level of the hierarchy, which is then subdivided into many subgoals as per necessities. Subgoals can be divided further until an appropriate discontinuing point is reached. The subgoals at any level of the hierarchy must completely describe the superordinate goals; conversely, a superordinate goal must be exhaustively described by its subgoals. Plans are inserted between levels to provide structure and order to the subtasks immediately below them. Essentially, a plan describes the way in which the subtasks combine to form the superordinate task. Thus plans are very important elements of HTA. It is useful, although not essential, to have access to the specifications for the design in question.