Multiple Stimulus without Replacement Preference Assessment (MSWO) - 40 Hour RBT® Online Training

Multiple Stimulus without Replacement Preference Assessment (MSWO)

A Multiple Stimulus without Replacement (MSWO) Preference Assessment is a method used in Applied Behavior Analysis (ABA) to identify an individual’s most preferred items by presenting an array of stimuli (typically 3-7 items) at once and allowing the individual to select one. After an item is chosen, it is removed from the array, and the remaining items are presented again in subsequent trials. This continues until all items have been selected or the individual chooses to stop. The frequency and order of selection are recorded to establish a hierarchy of preferences.

Example

A behavior analyst is conducting an MSWO preference assessment with a child named Sarah to identify preferred items that could be used as reinforcers during therapy sessions. The analyst selects five items: a puzzle, a stuffed animal, a toy car, a ball, and a piece of candy. All five items are presented to Sarah at once, and she chooses the piece of candy. The candy is then removed from the array, and the remaining four items are presented. In the next round, Sarah chooses the stuffed animal, which is then removed. This process continues until all items have been chosen or Sarah shows no interest in the remaining items. After several trials, it becomes clear that Sarah prefers the candy and stuffed animal the most, while the puzzle and ball are less preferred. The analyst uses this information to create a reinforcement plan that includes Sarah’s highest-preferred items.

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