Paired stimulus preference assessment
In a paired stimulus preference assessment, items are presented two at a time, and every item is paired with every other item, to produce a preference ranking.
Also called a paired choice or forced choice assessment, this format presents two items side by side and asks the client to choose one. The client gets brief access to the chosen item, and the next pair is presented. Across the assessment, each item is paired with each other item, and the left and right positions are balanced. Selections are recorded on a data sheet.
At the end, the RBT calculates the percentage of times each item was selected out of the number of times it was presented, and the items are ranked from most to least preferred. Because every item competes directly with every other item, the paired stimulus format gives a clear hierarchy and helps identify items that are moderately as well as highly preferred.
Its main limit is time: the number of pairs grows quickly with more items. Eight items require 28 pairs to present every combination once, and more if pairs are repeated. It also requires the client to scan two items and make a selection, so the supervisor may choose a different format for clients without those skills. If the client reaches for both items, the RBT blocks the attempt and re-presents the pair as the procedure specifies.
Example and non-example
| Example | An RBT holds up a bubble wand and a toy car, says "Pick one", gives 15 seconds with the chosen bubbles, then presents the car with a puzzle, continuing until all pairs have been shown. |
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| Non-example | Placing all six items in a row, letting the client choose, and removing the chosen one before the next trial is multiple stimulus without replacement. |
Don't confuse it with
| Multiple stimulus without replacement | Paired stimulus presents two items per trial; MSWO presents the whole array and removes each chosen item. |
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| Single stimulus preference assessment | Paired stimulus requires a choice between two items; single stimulus presents one item at a time and records approach. |
Test yourself
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Question 1In which preference assessment are two items presented at a time and the client chooses one of them?
Show answer
D: Paired stimulus. In a paired-stimulus (forced-choice) assessment, items are presented two at a time, and each item is paired with every other item. The client's choices are used to rank the items.
- A: Single-stimulus assessment presents one item at a time.
- B: MSWO presents an array of several items at once.
- C: A free-operant assessment makes all items available at the same time with no trials.
Task B.1 · 40-hour curriculum section D
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Question 2In a paired-stimulus assessment, a puzzle is presented 8 times and the client chooses it 6 times. What is the puzzle's selection percentage?
Show answer
C: 75%. Selection percentage = times chosen ÷ times presented × 100 = 6 ÷ 8 × 100 = 75%.
- A: 25% is the percentage of times the puzzle was not chosen (2 ÷ 8).
- B: 60% would be 6 out of 10, not 6 out of 8.
- D: 80% would be 6.4 out of 8, not 6 out of 8.
Task B.1 · 40-hour curriculum section D
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Question 3In a paired-stimulus assessment with 6 items, each item is paired once with every other item. How many times is each item presented?
Show answer
A: 5. Each item is paired once with each of the other 5 items, so it is presented 5 times (6 − 1 = 5).
- B: An item is never paired with itself, so it appears 5 times, not 6.
- C: 10 would mean each pairing was presented twice; here each item is paired once with each of the other 5 items.
- D: 15 is the total number of pairs in the whole assessment, not the number per item.
Task B.1 · 40-hour curriculum section D
Answer every question to see your score.
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.