Task Analysis

Hierarchical and Cognitive Task Analyses

Before you design or redesign a system, you should have a solid understanding of your system's goal, process of achieving that goal, and product requirements. One method of achieving this understanding is by conducting a Task Analysis.

Task Analysis (TA) is a method of identifying a system goal and studying a user's process towards achieving that goal, giving you useful insight on how a task is accomplished.

A TA gives you a deep knowledge of the processes and sub-processes behind achieving a task, and it should be conducted early in your system design process. By doing so, you ensure that you are working in the direction towards optimal usability. You will also be able to identify system requirements and the scope of the project after conducting the TA.

Types of Task Analysis

There are two main types of TA:

1. Hierarchical Task Analysis (HTA): Analyze a task by breaking it down into its observable hierarchical subtasks. HTAs are good for spotting inefficiencies prior to establishing product requirements. (More info here.)

2. Cognitive Task Analysis (CTA): Analyze the nature of tasks that require important cognitive processes, such as decision making, memory, attention, mental workload, and judgments. CTAs are good for understanding observable cognitive processes, informational system requirements, and performance differences between people with different experience levels. (More info here.)

Note: An Emotional Task Analysis (ETA) can also be conducted in conjuncture with a CTA to study unobservable emotional behaviors to each step and sub-step. (E.g. You can view a combined CTA and ETA I created after observing and interviewing a professional sports photographer here.)

Visualizations of TAs

TAs are typically displayed as tables and flow charts, though there are no real restrictions on how they should be visualized.

Conducting a TA

To conduct a TA you should structure your process ahead of time, with a process something along the following:

• Create a materials list of tools/objects that will be used in the TA

• Go out and collect contextual observations while users complete the task

• Conduct interviews with your users, discussing multiple task scenaries

• Document the observations and interviews (consider voice recording or filming, with permission)

• Create your TA

Complexity of a TA

How detailed and in-depth should you make your TA? Well, it depends on the stage you are in and the purpose of your analysis. On your first pass through a TA, you may keep things high-level; as you continue to iterate through, you may wish to add more sub-tasks and details in. If wish to use Scientific Management and understand every motion required to accomplish a task, you may wish to use an HTA and break things down to the Therblig level (More info here.)

So What's the Point?

Using a TA is a great approach when starting your human-centered design process, helping designers understand all of the physical and cognitive tasks and sub-tasks required to achieve a goal. This can help you notice inefficiencies and deficits that should be improved upon in your current system-process.

Simplistic TAs can also be performed in your everyday life—consider analyzing how you get ready in the morning or how you make breakfast. Is the order of your morning routine efficient? Are you repeatedly going between your bedroom, bathroom, and kitchen more than necessary? Is your kitchen organized in such a way that you find yourself walking constantly walking back-and-forth to get all of the ingredients and utensils?

One last side note: don't limit yourself by assuming your TA is the only method of accomplishing a task. Allow yourself to 'think outside the box' and brainstorm new methods of task processes from time-to-time, so that you are not only considering the exact TA process you devised.