What are preference assessments, and why should I conduct them?
For older children and typically developing children, it is often simple to determine potential reinforcers (i.e., items that will reinforce targeted behaviors). Often, you can just ask them what they like or want to work for! For younger children and children with disabilities, potential reinforcers are sometimes less obvious. Commonly assumed reinforcers—like tokens and social praise—might not be reinforcing for children with disabilities, and in fact, may even punish appropriate behaviors! Preference assessments are observations or trial-based evaluations that allow practitioners to determine a preference hierarchy. A preference hierarchy indicates which items are a child’s highly-preferred items, moderately-preferred items, and low-preferred items. Sometimes (but not always), the child’s most preferred items can be used to reinforce a child’s appropriate behaviors. Preference assessments can be used to determine hierarchies for toys, edible items, social interactions, activities, caregivers, locations, and more, but this description will focus primarily on five types of preference assessments typically conducted with toys or edible items:
Multiple Stimulus without Replacement (MSWO) Preference Assessments
Multiple Stimulus with Replacement (MSW) Preference Assessments
Paired Stimulus Preference Assessments
Single Stimulus Preference Assessments
Free Operant Observations
Generally, preference assessments with edible items (food) are conducted separately from preference assessments with tangible items (toys). Teachers typically reinforce a single targeted behavior with edible OR tangible items, but not both. Additionally, preference assessments are conducted slightly differently—with edibles, items are consumed and need not be taken away; with toys, items are taken back after a predetermined time period. Note: When conducting edible preference assessments, always wear gloves and put food items on a hygienic surface (e.g., paper towel or large plate).
What is the difference between a highly-preferred item and a reinforcer?
Preference assessments can be used to determine preference hierarchies from a limited group of items. Preference assessments can only determine a rank of the items you test, and the items you select are not guaranteed to be reinforcers. For example, if a teacher gives a choice of six vegetables to a child who dislikes vegetables, he may still make selections during a preference assessment, even though he would be unlikely to perform academic tasks to obtain them. To make it more likely that your preference assessment will determine reinforcers, be sure to include items you think may be highly preferred by the child. If you are not sure what items the child prefers, perform a Free Operant Observation first.
Preference assessments are designed to determine hierarchies under the specific set of circumstances in which they are conducted. For example, a child may indicate highly preferred food items before lunch, but refuse to “go potty” to obtain the food items immediately after lunch. Likewise, children’s preferences change frequently, as they satiate on toys they’ve played with more frequently and discover new and interesting toys. As discussed on the “Differential Reinforcement” page, to prevent frequent satiation on reinforcers, it may be helpful to make the child’s highest preferred items available contingent on targeted behaviors (i.e., when intentionally reinforcing targeted behaviors that are of considerable importance).
How often should I conduct preference assessments?
You can assess reinforcers very frequently (e.g., during every instructional session) or
less frequently (e.g., once per month). You should conduct assessments more often for children whose preferences seem to change regularly or when a child’s behavior shows that a former reinforcer may no longer be preferred (e.g., not engaging with an item when allowed to do so, not consuming a previously-preferred edible).
In addition to the formal preference assessments described on the following pages, you can also conduct informal assessments even more frequently. Before an academic session, for example, you can show laminated pictures of two or three highly-preferred edible items, and ask the child which one he would like to work toward. Before placing a demand (e.g., going potty), you can show the child a box of his special toys and let him pick which one he’ll get after completing the demand. This sort of informal assessment ensures that the reinforcers you offer are consistent with the child’s changing preferences.
Additionally, for children with adequate expressive language, you can check in frequently with the child about his or her preferences. For children who are not fluent verbal communicators, you can check in frequently with parents or other practitioners to determine whether they have noticed any changes to the child’s preferences.
How do I know which kind of preference assessment I should conduct with my child?
The following pages will provide an overview of five preference assessments: (1) multiple stimulus without replacement (MSWO), (2) multiple stimulus with replacement MSW), (3) paired stimulus, (4) single stimulus, and (5) free operant.
Multiple Stimulus without Replacement (MSWO) Preference Assessments are appropriate for children who can adequately select preferred items among a sizeable array of items. For assessments with tangible items (i.e., toys), it is also appropriate for children who do not engage in challenging behavior when preferred toys are taken away. For children with the prerequisite skills, this is the fastest and most accurate way to determine a hierarchy for a large number of items. However, if a child engages in problem behavior when preferred toys are taken away, an MSW should be used. If a child is able to select highly-preferred items over low-preferred items but is unable to scan more than two items on a surface, a Paired Stimulus Preference Assessment should be used. If a child is unable to choose highly-preferred items over low-preferred items, or demonstrates a side bias (i.e., selecting items only on one side), a Single Stimulus Preference Assessment or Free Operant Observation should be used.
Multiple Stimulus with Replacement (MSW) Preference Assessments are also appropriate for children who can adequately select preferred items among a large array of items. For tangible items (i.e., toys), it is also appropriate for children who do engage in challenging behavior when preferred toys are taken away. Though an MSW is more time-consuming than an MSWO, the child always has the option to choose the same toy, which may prevent challenging behavior or damaged rapport with new practitioners. However, if a child is able to select highly-preferred items over low-preferred items but is unable to scan more than two items on a surface, a Paired Stimulus Preference Assessment should be used. If a child is unable to choose highly-preferred items over low-preferred items, or demonstrates a side bias (i.e., selecting items only on one side), Single Stimulus Preference Assessments or Free Operant Observations should be used.
Paired Stimulus Preference Assessments are appropriate for children who can adequately select preferred items from an array of two. In order to assess whether a paired stimulus preference assessment would be appropriate, present known highly-preferred items and known low-preferred items side-by-side to the child, and assess whether the child consistently chooses the highly-preferred item over the low-preferred item. Generally, paired stimulus preference assessments more accurately determine a child’s preferences than single stimulus preference assessments. However, if a child is unable to choose highly-preferred items over low-preferred items, or demonstrates a side bias (i.e., selecting items only on one side), Single Stimulus Preference Assessments or Free Operant Observations should be used.
Single Stimulus Preference Assessments also known as “successive choice” assessments, are appropriate for children who are unable to select between highly-preferred and low-preferred items. These are also appropriate for children who engage in challenging behavior when preferred toys are taken away, because children are allowed to continue engaging with toys until they choose to stop or give them up. These may not be appropriate if you have limited time to conduct assessments.
Free Operant Observations are appropriate for all children, and are simple observations to do regularly in a classroom setting if an observation can be scheduled during a time when a child has the opportunity to choose among many different, possibly reinforcing, items or activities (e.g., free play). These are appropriate assessments for children who engage in challenging behavior when preferred toys are taken away, because items are never removed after selection or engagement. It may also be appropriate to be conducted by a child’s new practitioner, as he or she may be unable to identify an array of likely reinforcers without prior observation of the child.
To cite this page (APA 6th edition):
- Chazin, K.T. & Ledford, J.R. (2016). Preference assessments. In Evidence-based instructional practices for young children with autism and other disabilities. Retrieved from http://vkc.mc.vanderbilt.edu/ebip/preference-assessments