Task analysis

Depending on the kind of product to be designed, a task analysis might consist of one or more of the following components: hierarchical task analysis, task decomposition, goal-based task analysis and cognitive task analysis. The task analysis for a specific project might consist of only one of these techniques. When combining all techniques for the more complex projects where e.g. information needs and cognitive demands are to be analysed, the techniques are preferably applied in order of complexity (start with the easier techniques and continue with the techniques that require a more profound analysis). The roadmap for a complete task analysis looks as follows:

• Task analysis preparation - defining the goal of the task analysis and the questions to be answered, getting familiar with the context and work domain by reading documentation, manuals, procedures, by following a training, doing an exploratory observation...
• Hierarchical task analysis – focusing on what the user actually does and how these tasks can be structured in a logical way; the result of a hierarchical task analysis mostly is a tree structure of activities, tasks, actions, etc.
• Task decomposition – specifying characteristics of each task in the hierarchical task analysis in a systematic way; examples of characteristics are the required information, skills and hardware, required decisions, complexity, frequency, required speed and accuracy, expected outcome and feedback, occurring problems...
• Goal-directed task analysis – focusing on the user's motivations, what he/she wants to achieve, which decisions need to be taken and what information he requires therefore
• Cognitive task analysis – focusing on the required knowledge and cognitive demands of tasks, the interaction points where errors are likely to occur, and the strategies people follow to avoid or solve these errors.
• Task analysis reporting - interpreting the analysis, transforming the analysis outcome into a presentable and/or readable form and communicating it

Hierarchical task analysis and task decomposition form the basis of task analysis. These two techniques enable to form a good understanding about the tasks to be performed, their characteristics and the work domain in which they fit. In case situation awareness and cognitive demands are considered to be critical aspects of the interaction, goal-directed and cognitive task analysis become relevant. These techniques enable to specify the task elements where information or knowledge misses and where cognitive problems are likely to arise, so the designer can focus on these aspects to improve the system and support people in a better way.