Multiple stimulus with replacement
In a multiple stimulus with replacement (MSW) preference assessment, several items are presented together, and the chosen item is returned to the array before the next choice.
The procedure begins like MSWO: an array of items is placed in front of the client, who chooses one and has brief access to it. The difference is that the chosen item goes back into the array, while items that were not chosen may be swapped out for new ones, depending on the procedure. Positions are rearranged between trials so that choice is not simply based on location.
Because the most preferred item stays available, a client may choose it on every trial. That makes MSW quick at identifying the single most preferred item, but it gives less information about the rest of the hierarchy, since lower-ranked items may never be selected. It can be a useful way to confirm a top choice before a session.
RBTs record which item is chosen on each trial and summarize the number or percentage of selections per item. The supervisor decides when this format is appropriate. As with all preference assessments, the result shows what the client selected at that moment, not proof that the item will function as a reinforcer.
Example and non-example
| Example | An RBT lays out a tablet, a ball and a book. The client picks the tablet, plays for 30 seconds, then the tablet is put back with the other items in new positions, and the client picks the tablet again. |
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| Non-example | Removing the tablet after it is chosen so the client must pick between the ball and book is MSWO. |
Don't confuse it with
| Multiple stimulus without replacement | MSW returns chosen items to the array; MSWO removes them, which produces a full ranking. |
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| Free operant preference assessment | MSW records discrete choices in trials; free operant measures how long the client engages with freely available items. |
Test yourself
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Question 1An RBT places six items in a row in front of a client. The client picks one, plays with it briefly, and the item is then left out while the remaining items are rearranged for the next trial. Which preference assessment is this?
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D: Multiple stimulus without replacement. In MSWO, a selected item is not put back. The client chooses from fewer items each trial, and the order of selection produces a ranking.
- A: In MSW, the chosen item is returned to the array for the next trial.
- B: A paired-stimulus assessment presents only two items per trial.
- C: A free-operant assessment has no trials or selections; items are freely available.
Task B.1 · 40-hour curriculum section D
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Question 2A client chooses from an array of five toys. After each brief play period, the RBT puts the chosen toy back in the array with the others for the next trial. Which preference assessment is this?
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B: Multiple stimulus with replacement. Returning the chosen item to the array on every trial is what defines multiple stimulus with replacement (MSW).
- A: A paired-stimulus assessment presents two items per trial.
- C: Single-stimulus assessment presents one item at a time.
- D: In MSWO, the chosen item is left out of the array.
Task B.1 · 40-hour curriculum section D
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Question 3In a multiple-stimulus-with-replacement assessment, a client picks the same tablet on nearly every trial. What is the main limitation of the results?
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C: They show little about how the other items rank. Because the chosen item returns to the array, a strongly preferred item can be picked every time. MSW identifies the top item but gives little information about the relative preference of the rest.
- A: Preference does not prove reinforcing effects for every task.
- B: Consistent choice of one item does not show misunderstanding.
- D: Choosing the tablet repeatedly suggests it is highly preferred.
Task B.1 · 40-hour curriculum section D
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On the RBT exam
This term belongs to task B.1 Preference assessments in content area B, Behavior Assessment, which is 8 of the 75 scored questions.