TASK ANALYSIS II

Task analysis analyses what a user is required to do in terms of actions and/or cognitive processes to achieve a task. A detailed task analysis can be conducted to understand the current system and the information flows within it. These information flows are important to the maintenance of the existing system and must be incorporated or substituted in any new system. Task analysis makes it possible to design and allocate tasks appropriately within the new system. The functions to be included within the system and the user interface can then be accurately specified.

In the class we make some activities where this can help us to improve and create and provides knowledge of the tasks that the user wishes to perform. Thus it is a reference against which the value of the system functions and features can be tested.

Method

Task decomposition

The process of task decomposition is best represented as a structure chart (similar to that used in Hierarchical Task Analysis). This shows the sequencing of activities by ordering them from left to right. In order to break down a task, the question should be asked ‘how is this task done?’. If a sub-task is identified at a lower level, it is possible to build up the structure by asking ‘why is this done?’. The task decomposition can be carried out using the following stages:

1. Identify the task to be analysed.

2. Break this down into between 4 and 8 subtasks. These subtasks should be specified in terms of objectives and, between them, should cover the whole area of interest.

3. Draw the subtasks as a layered diagram ensuring that it is complete.

4. Decide upon the level of detail into which to decompose. Making a conscious decision at this stage will ensure that all the subtask decompositions are treated consistently. It may be decided that the decomposition should continue until flows are more easily represented as a task flow diagram.

5.Continue the decomposition process, ensuring that the decompositions and numbering are consistent. It is usually helpful to produce a written account as well as the decomposition diagram.

6. Present the analysis to someone else who has not been involved in the decomposition but who knows the tasks well enough to check for consistency.