Hierarchical Task Analysis (HTA)

Task analysis methods allow you to learn more about how a user performs a task and achieves their goals, typically through observing them perform the task of interest. This can help you gain insight into the goals that the user is trying to achieve, what users actually do (not what they should do) to achieve those goals, and the influence of prior knowledge and experience on how the user performs the task.

Below is an example of a task analysis method in action:

• Hierarchical Task Analysis (HTA)

Hierarchical Task Analysis (HTA)

This is one of the most popular methods for task analysis. HTA involves decomposing a task from a goal into subgoals and task components. Because the information is hierarchical, HTA is often presented as a flow chart or task table with each step listed in the left-hand column. Researchers may also choose to include additional information relating to each task component, with additional columns added to the right of the steps presented in the table or chart (e.g., potential errors, likelihood of occurrence, consequence of an error occurring, or recommended solutions). Although the hierarchical structure presents a sequential list of steps, alternative task steps or actions can be presented to illustrate different possible paths in the case of an error or constraint.

Before creating the task description, I developed a task lexicon to ensure each action term used was used consistently and was explicitly defined. My construction of the task description was a series of iterations where I started with a general, very high overview of the task, then went back and added more steps until I felt satisfied that I had listed all of the relevant actions that our organization took to successfully order t-shirts. After I was satisfied with the description I conducted a tabular hierarchical task analysis in which I listed each step outlined in the task description, followed by a list of potential errors at each step in the process, their potential consequences, and the relative criticality of that error. Highly critical errors were defined as those that would prevent the task of ordering t-shirts from being completed or result in disciplinary action. Low criticality errors are those that would be considered irritating or result in duplication of work, but would not prevent completion of the task.

From this analysis I discovered two main phases within the task: the research and development (R&D) phase (highlighted in yellow), and the purchasing phase (highlighted in green). The R&D phase presented several opportunities for highly critical errors to occur. This suggests that this phase is very important for organizations to consider carefully before proceeding to the purchasing phase and that solutions should be implemented to reduce the likelihood of errors in this phase (e.g., licensing office conducting outreach to student organizations to alert them of trademark regulations and university rules).

Things to remember:

• The level of granularity in a HTA should be based on your research goals. For example, if I was interested in evaluating a t-shirt ordering interface I may choose to include details about page navigation (e.g., clicking on website elements). On the other hand, if I am interested in creating a checklist of actions for other organizations to follow, then the level of detail in the task description shown below should be sufficient. The HTA will not be useful if the task description does not have a sufficient level of detail, but getting more detailed than necessary will take up valuable time and resources without offering significant return on investment. If you find that you are struggling to conduct a meaningful analysis, try returning to your task description to refine the level of detail.

• Data can be collected through a variety of methods, such as observation, subject matter expert input, and walkthroughs.

Pros:

• Easy to create and implement

• Useful starting point for other analyses (e.g., error analysis)

• Provides useful information about a user's goals, plans, and operations while doing a specific task or interacting with a particular system

Cons:

• Can get quite lengthy, and therefore require significant time and resources, when dealing with more complex tasks

• Error criticality is often based on the judgement of the researcher

References:

1. French, A., Taylor, L. K., & Lemke, M. R. (2019). Chapter 6 - Task analysis. In M. B. Privitera (Ed.), Applied Human Factors in Medical Device Design (pp. 63-81). Academic Press. https://doi.org/10.1016/B978-0-12-816163-0.00006-2

Task Description:

Step 1 - Determine member interest in acquiring organization t-shirts

Do members approve of the proposed design?

Are members willing to pay to obtain a shirt?

Step 2 - Research NC State University’s trademark licensing rules and regulations

Step 3 - Determine if student organization meets criteria for trademark use

Step 4 - Determine if the logo design violates any of the established rules or regulations

Step 5 - Adjust the logo design to adhere to the rules and regulations, if necessary

Step 6 - Choose final logo design

Step 7 - Confirm purchase intent with members based on final logo design

Step 8 - Identify NC State University's pre-approved licensed vendors*

Step 9 - Research available styles and typical prices for t-shirts through pre-approved licensed vendors

Step 10 - Identify most valued characteristics in a t-shirt with product stakeholders

Step 11 - Identify t-shirt styles that meet stakeholder-identified characteristics

Step 12 - Identify t-shirt materials that meet stakeholder-identified characteristics

Step 13 - Choose desired t-shirt style

Step 14 - Choose desired t-shirt material

Step 15 - Choose an approved vendor to purchase t-shirts from based on availability of t-shirts with the chosen style/material

Step 16 - Submit the Trademark Licensing Office’s Trademark Use Request Form

Step 17 - Identify cost of available t-shirt options with specified style/material through chosen vendor

Step 18 - Choose product based on option with best price

Step 19 - Confirm required sizes are available for best priced option

Step 20 - Identify organization’s existing budget for purchasing t-shirts

Step 21 - Determine how much additional revenue is needed to purchase t-shirts based on previously identified purchase intent and chosen product

Step 22 - Determine t-shirt cost per member

[Total order cost - Budget]/Number of members purchasing a shirt

Step 23 - Confirm t-shirt cost and order sizes with members

Step 24 - Submit t-shirt order through vendor

Step 25 - Confirm order is accepted by vendor

Step 26 - Collect t-shirt payment from members

Step 27 - Collect t-shirt order from vendor

Step 28 - Distribute t-shirts to members

*a licensed vendor is required to use NC State trademarks on apparel