Task Decomposition


A task decomposition describes a particular task and then decomposes it to describe the task's features, such as devices and interface components used, duration, errors, and feedback. These categories will be selected by the analyst based on the needs of the analysis.


To collect detailed information about a specific task.

To break down a task into its component features.

How do I use this tool?: 

1. HIERARCHICAL TASK ANALYSIS (HTA). Describe the task under analysis using an HTA.

2. CREATE TASK DESCRIPTIONS for each task step. The HTA from the previous step may be useful here. The description should let the analyst know exactly what has been done to complete the task step.

3. CHOOSE DECOMPOSITION CATEGORIES. Some types of categories include: descriptive, organization-specific and modeling.

4. INFORMATION COLLECTION. The analyst should record task descriptions and collect pertinent information for each decomposition category.

5. CONSTRUCT TASK DECOMPOSITION. Collected data should be transferred to a task decomposition output table.

Expertise Required: 
Users of this tool usually have some training or experience in its use.

Can provide a comprehensive analysis.

Is flexible and easy.

Is generic across nearly all domains.


Can be time consuming.

Where can I go to learn more?: 

Stanton N, Salmon P, Walker G, et al. Task analysis methods. Human factors methods: a practical guide for engineering and design. Great Britain: Ashgate; 2005. p. 45-76.