What is a task system?


The key to successful task analysis is proper to properly frame the task system that contains the tasks you want to analyze.  


Task systems do not live in a vacuum.  They typically reside within larger task systems and receive inputs and produce outputs.  The purpose of the task system is defined by the larger task system.  This is why there are three hierarchical levels in any task analysis:

  1. A Goal describes the purpose of the task system.
    1. Tasks represent the interactions between the task system components.
      1. Sub-tasks that break down each task further to allow analysis of the tasks in the system.


Even a simple goal contains three parts to be fully descriptive.  It describes the outcome to be achieved, it identifies any constraints or rules that the system must abide by while achieving it's purpose, and it provides how success will be evaluated.  Many times these rules are not explicitly stated in a goal description, but they are there nonetheless.

Task systems also have inputs and outputs.  Once you have framed the task system by identifying the goal of the system, it's components, and their interactions; you must consider the inputs and outputs. The inputs are the things that enter the system, and the outputs are those things that leave the system.

Let's look at a simple task system.  Suppose we want to analyze how we change the ink cartridge in your printer.  It is assumed that you will obtain a suitable ink cartridge and dispose of the empty cartridge properly.  Our measure of success is to be able to do this task quickly.  From this simple goal statement, we can infer the following system components:  A printer, a fresh ink cartridge, an empty ink cartridge, and a person to complete the task.  The fresh ink cartridge is an input, and the empty ink cartridge is an output.  The sequence of tasks will describe how the system components interact to achieve the intended goal.   Sub-tasks can now be defined for the purpose of analyzing tasks in the sequence.  A goal statement for this task system might look like this.

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