One of the most critical aspects of any ABA program is rewards! These are most often items that your kiddo loves to engage in (activities), play with (toys), or partake of (food), and can be provided for good work or appropriate behaviors. To identify potentially effective rewards, ABA practitioners often use preference assessments that involve the child choosing from an array of items. One of the more simple and time efficient assessments is the Multiple Stimulus Without Replacement (MSWO) method. This method is easy for teachers and parents to implement and is relatively quick.

It is important to note that preferences can change over time! So making a preference assessment a part of your weekly routine is recommended.

Ensure that those rewards are actually rewarding, and even to identify new, more preferred items. As such, knowing how to conduct a quick assessment can come in handy.

Here are some simple steps for doing the MSWO. Be sure to use items the child does not come in contact with on a regular basis but you know he/she would go bonkers whenever they do get an opportunity to contact it.

How to:

Step 1: Gather an array of items (toys, edibles, etc.)

Step 2: For items that are very new to the child, allow him/her to sample it (a small piece of an edible, or 30 seconds engaged with a toy or in an activity).

Step 3: Wait 3 minutes after sampling is complete. During this time you can take out samples of all the edible items (e.g., placing a small amount in a cupcake cup/Ziploc baggie/Cling wrap etc.). [PICS!]

Step 4: Have the child seated across from you and ask him/her to sit quietly, hands in lap, and don’t touch anything until you instruct him/her to do so.

Step 5: Once your kiddo is seated quietly with hands in lap, giving you full eye contact as he/she waits in anticipation, line out all the items before him/ her (repeat, “remember, don’t touch till I say so.”). Ensure all items are placed, evenly spaced, and no item is too far out of the child’s reach.

Step 6: Once all items are laid out, say “Ok! Choose ONE!”

Step 7: Once your child chooses an item, allow him/her a few seconds to partake of it while you write down what he/she chose.

Step 8: Rearrange the remaining items before your kiddo as described in step 5. DO NOT INCLUDE THE PREVIOUSLY CHOSEN ITEM IN THE UPCOMING TRIAL.

Step 9: Repeat step 6-8 until all the items have been chosen.

Step 10: You should now have a rank order of items, from first choice, to second choice, third choice … etc.


The rank order of items you derive will be an indicator of you child’s relative preference of those items. The first choice being their most preferred item, and the last choice being their least preferred. Have fun! 🙂