The Wonders of Preference Assessments

Preference assessments are fabulous tools for anyone looking to change someone's behavior. I've used them in the classroom, in adult services, and even with my dog! (more on that below). Keep reading for the what, why, and how for preference assessments.

What are preference assessments?

Preference assessments are tools that help to determine a preference hierarchy of potent reinforcers for learners with a variety of abilities. This hierarchy indicates which items/potential reinforcers are highly-preferred, moderately-preferred, and low-preferred. Generally however, I conduct these assessments with items/activities that the individual or caregiver reports is somewhat preferred, so you usually don't have a "low-preferred" item, and rather just not as preferred as the others. 

Why preference assessments?

Determining this hierarchy is important to support any behavior change protocols, as the individual will be more likely to work for highly-preferred reinforcers. And note, I emphasize the individual here, because this, like many other topics I discuss, needs to be individualized. What works for one learner, may not/will not work for another. I could work all day every day for a bowl of watermelon (provided I don't have access to it whenever I want - a topic for another day). My husband? No way would he do anything for watermelon. A brownie, yes. And yeah, maybe I'd work for a brownie too, but if I was deprived of watermelon (think: start of Summer, when it's finally in season...) I'd probably choose that over the brownie as something to earn after I clean the bathroom.

So why not just ask? Why the whole to-do with an assessment?  Well, for a few reasons.Often, these assessments are used with people (or animals) that have limited communication abilities. Additionally, they may have restricted interests and would not be able to "think" about other things they might like. Aside from their restricted interests, they may not have been exposed to a variety of novel, potentially reinforcing items, therefore don't know they like or can ask for them.

These assessments are key. The effectiveness of any behavior plan or skill acquisition program depends on the reinforcement procedures. People work for things. You need to find out what those things are. And this is the tool to help you with that!

How do I run and use preference assessments?

First you need to determine the type of preference assessment you want to run for your learner. There are two different types of assessments: indirect and direct assessments. Generally, I will run both. An indirect assessment means that you are indirectly determining potent reinforcers by asking the caregiver or staff, sometimes the individual themselves. Usually, I will use this information to narrow down which items I will present in the direct preference assessment I choose. Direct measures include single-stimulus preference assessment, paired-preference assessment, multiple stimulus without replacement (MSWO), duration-based preference assessment, and free-operant preference assessment. I won't go through each one - that's a talk for another day. Today I will talk about the ones I use the most.

Paired Stimulus (Forced Choice)

I used forced choice preference assessments almost exclusively. This is a trial-based method for preference assessment, which means the stimuli are presented to the learner in a series of trials and the responses to these stimuli are measured and ordered by preference.Each trial in a forced choice assessment consists of the simultaneous presentation of two stimuli/items. The practitioner records which of the two the learner chooses (or which one he/she chooses first if the learner ended up grabbing both before you could stop em!). During this assessment, each stimulus is matched randomly with all other stimuli in the set. This provides data that show how many times each stimulus was chosen. The stimuli are then ranked by preference. Studies have shown that forced choice assessments sometimes outperform successive choice assessments in identifying potent reinforcers, as well as yield more accurate distinctions between preferences (high vs. moderately vs. low-preference reinforcers) (Pace et al., 1985; Piazza et al. 1996; Paclawskyj & Vollmer, 1995). While it may seem that this assessment may be time consumer, I've found that since I am most familiar with this one, it's a breeze for me to complete. As long as you have your items and materials ready to go, this won't take any more time than the others. Plus - the data analysis is super easy!

Check out this video of me running a forced choice preference assessment with my dog Lucy. I used the most high-preference reinforcer (as determined by this assessment) for some behavioral programming I did with Lucy (such as identifying and retrieving toys by name). Worked like a charm!

Single Stimulus (Successive Choice)

This assessment is another trial-based preference assessment and is considered the most basic preference assessment available. For this assessment, a stimuli/item is presented and the learner's response to the stimuli is recorded. These stimuli are presented one at a time, in random order. Generally, the data collection is more involved, as it requires the practitioner to note the approach vs.. rejection behavior, frequency of interaction, and/or duration of play/engagement. After recording, the next item in the sequence is presented. This assessment may be helpful with learners who have difficulty with selecting among an array of items.

Free Operant

Essentially, this assessment evaluates the activities that the learner engages in most often when able to choose freely and their effect on behavior. The idea is that whatever someone chooses to spend their time doing, can be used as a potent reinforcer when made contingent on engaging in a low-probability behavior. The assessment requires the practitioner to observe the learner and record the activities they are engaging in when given free-reign of his/her environment. In order to determine the preference hierarchy, the practitioner records the duration the learner engages with each activity; the longer duration, the more likely it is "preferred". Ordering the durations from longest to shortest will give you a hierarchy of preferred items from highly preferred to less preferred. This assessment can be great when you may not have a set list of potential reinforcers to test (no opportunity for indirect measures). I also use this assessment for when new ABA therapists start so they can begin to build rapport with the individual (as these assessments are generally seen as less intrusive and, well, free play. Additionally, this is a great one to use in a natural setting and with ABA therapy practices (or classrooms) that do not have it in their budget to go out and buy special items to use as potential reinforcers.

With any new program, I always run a preference assessment. I often re-run them as well as time goes on, to ensure I still have the most potent reinforcer, or if I need to change things up. It may take some time to get used to running them, but if you practice it at home (like I did) and cut yourself some slack while you are running them, they will become easy and you will see why they are so important! Why guess at what might be reinforcing for a learner and probably get it wrong, and waste more time grasping at straws? This is why this tool is so handy - it allows us to get right down to the bottom of the reinforcement question to make our behavior planning easier and more efficient.

Check out these resources for some samples (note I did not make these data sheets)

Indirect Preference Assessments: 

• Reinforcer Preference Assessment (Secondary Level)
• Reinforcement Inventory
• Reinforcer Assessment for Adults

Direct Preference Assessment Data Sheets:

• Forced Choice Preference Assessment (from Evidence-Based Instructional Practices)
• Successive Choice Preference Assessment  (from Evidence-Based Instructional Practices)
• Free Operant Preference Assessment (from Evidence-Based Instructional Practices)

References:

Chazin, K.T. & Ledford, J.R. (2016). An overview of evidence-based instructional practices (EBIPs). In Evidence-based instructional practices for young children with autism and other disabilities. Retrieved from http://vkc.mc.vanderbilt.edu/ebip/

Cooper, J. O., Heron, T. E., & Heward, W. L. (2008). Applied behavior analysis. Upper Saddle River, NJ: Pearson/Merrill-Prentice Hall.

ABA at Play: scientific research, evidence-based practices, preference assessment, behavior change procedures, socially significant behavior, individualized supports, reinforcement procedures, discrimination, operant behavior, video modeling