Task analysis :: 2 of 2

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Benefits of task analysis
Task analysis provides detailed diagrammatic knowledge of the tasks that a user performs or wishes to perform. Thus, it is a reference against which the value of the system functions and features can be tested.

It is often used to identify the tasks and actions - associated with a particular goal or goals - prior to conducting a cognitive walkthrough of a concept, prototype or beta release.

Look out for...
There is no right or wrong about task analysis, but there is good and bad task decomposition. For example, decomposing a ticket-ordering task into subtasks involving the use of spades or white ticker tape is probably a bad idea! The following are good pointers for constructing robust task decomposition:

• Be iterative - don't try to get to the simplest level of sub-tasks in one go. Allow the decomposition to proceed by a number of small steps
• Remember the goal - the aim of the technique is better understanding of a person's cognitive processes, not a huge, richly annotated diagram that covers the entire wall
• Aim for simplicity - task analysis should decompose a task into simpler component subtasks. If you find you're creating sub-tasks that are more complicated than the high-level task, you're doing something wrong!

Good books

Hackos, J. & Redish, J. (1998) User and Task Analysis for Interface Design. Chichester: Wiley.

Kirwan, B. & Ainsworth, L.K. (Eds.) (1992) A Guide to Task Analysis London: Taylor and Francis.

Shepherd, A. (1985) Hierarchical task analysis and training decisions. Programmed Learning and Educational Technology, 22, 162-176.

Shepherd, A. (1989) Analysis and training in information technology tasks. In D. Diaper (Ed) Task Analysis for Human-Computer Interaction, pp.15-55. Chichester: Ellis Horwood.

Nielsen, J (1994) Extending Task Analysis to Predict Things People May Want to Do

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