Multiple Stimulus with Replacement (MSW) Preference Assessment
An MSW Preference Assessment allows a teacher to create a hierarchy of the child’s preferences. Like an MSWO Preference Assessment, this is an appropriate assessment for children who are able to select preferred items among a sizeable array of items. Unlike an MSWO, this is an appropriate assessment for children who 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. Typically, an MSWO is a more efficient option for edible items, even for children with challenging behavior, because no items need to be taken away after the item is consumed. The drawback of the MSW is that a child may always pick a single item, which gives you information about the status of that item (the child highly prefers it) but no information about relative preference of the other items.
If a child is able to choose 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 conducted.
In an MSW Preference Assessment, the teacher places an array of items (usually toys or edibles) in front of the child, and allows him or her to select one. After the child plays with or consumes the item, the teacher replaces that same item in the array, and replaces the unselected items with new ones. Each time the teacher presents the array, this is known as one trial. The teacher repeats trials until the set number of trials is complete (e.g., after every item has been presented at least twice), or until the child refuses to make any further selections. Typically, the items the child selects during the most number of trials are the child’s highest preferred items of the array, and the items the child selects for the fewest number of trials are the child’s lowest preferred items. The highest preferred items are more likely to serve as reinforcers, or items that will reinforce targeted behaviors. However, keep in mind that not all preferred items function as reinforcers. It is important to (a) perform MSWs regularly because preferences may change, (b) assess a possible side bias by rotating the locations of chosen items, (c) use a combination of likely preferred and non-preferred items to confirm that the child is making choices based on preference, and (d) regularly assess whether you are able to remove preferred toys from the child without problem behavior, as MSWOs are more efficient than MSWs.
Before beginning, you should collect the following materials:
Data collection sheet
An array of 6-8 bite-sized edible items or 6-8 toys
Now you and your child are ready to begin.
- Sit across from the child at a table or on the floor.
- Place 3-4 items in a straight line within the child’s reach, in order by assigned letter. If the child is unable to wait until your task direction to make a selection, block view of the items with a large book or clipboard.
- Lift the book or clipboard (if you are blocking the child’s view), and give the task direction, “Pick one” or “Which one do you want?”
- If the child reaches for more than one item, block access to both items, and repeat the task direction, “Pick one” or “Pick one for now. We’ll pick another one next.” If the child continues to make this error across several trials, you should consider conducting a Single Stimulus Preference Assessment or Free Operant Observation.
- Allow the child to consume the edible item or play with the toy. Block access to the remaining stimuli during this interim.
- While the child is consuming the edible item or playing with the toy, replace the unselected items with new items, and choose a new location for the chosen item in the array. This will allow you to detect if the child is only choosing from one side.
- If you are using toys, put the chosen toy back in the array after 15-30 seconds. If you are using edibles, replace the chosen edible with an identical edible in the array. Thus, for every trial, you will have the same number of items as the previous trial, and the array will always include the most recently selected item.
- Repeat steps 4-7 until the set number of trials is complete (e.g., after every item has been presented least twice), or until the child refuses to make any further selections.
To cite this page (APA 6th edition):
- Chazin, K.T. & Ledford, J.R. (2016). Multiple stimulus with replacement (MSW) preference assessment. In Evidence-based instructional practices for young children with autism and other disabilities. Retrieved from http://vkc.mc.vanderbilt.edu/ebip/multiple-stimulus-with-replacement