Physiology of an HTA

How does it work?
Physiology has to do with functions and activities (usually in relation to a living organism). As mentioned in section 2 of What is HTA?, we said there is a systematic approach to completing this analysis. Let's look closer into what exactly that approach entails in terms of functions and activities.

Before the fun can begin, we have to record general information about the task. You should record:


 * The date and time
 * Where the task takes place
 * Information about the person completing the task (name, title, age, disabilities if any, etc...)

Once you have all that good stuff recorded, it's time to get down to business! It may be helpful to use a task analysis worksheet when completing an HTA. This was developed by the Natural Resources Conservation Service. Use one of these worksheets for practice during our scenario below.

Self-Check
Imagine if you will the task of making a peanut butter and jelly sandwich. If you can get someone in the house to make you a sandwich, please tell me how to do this! It will also be good practice for your first HTA.

The first subtask would be locating the bread. This subtask would be composed of elements such as opening the fridge (if that's where this person keeps their bread), opening the bag, taking out two slices of bread, closing the bag, etc... Your goal here is to simply observe and be as least intrusive as possible. If the person completing the task stops to ask you something, this will raise inconsistancies in your analysis, especially with the timing factor. Your HTA should look similar to this:



Other factors to watch for include unnecessary interruptions or tangents the worker may find such as locating a tool when it is not in its proper place. For instance, a butter knife. Why do they all have to be dirty when I want to use one?! Record the time it takes the person you're observing to wash a knife in order to use it.

Once you have finish what you feel is a completed HTA or task decomposition, you may want to walk through the entire process again with the worker completing the task. However, this time, only use your HTA as a guide. This will reveal further inconsistancies. Take our above task of making a peanut butter and jelly sandwich. We said the first subtask was to locate the bread. Following an HTA that states this as the first subtask would clearly show one had forgotten to record the subtask of locating a paper towel or plate as to not build the sandwich directly on the counter. For all you know, there could have been some raw chicken juice on that counter last night!

I'm done! Right?
Not so fast. You will notice toward the bottom of the worksheet it asks you to describe functional behaviors. This will aid you in developing your performance objectives, which will be discussed in the last section--Objectives Are Not Subjective.

Get another worksheet ready. You will need it for the final check portion.

Click next to continue.