2 Preference Assessments

Purpose and limits

A preference assessment identifies items or activities a person is more likely to choose or engage with under particular conditions. Results can help identify potential reinforcers for teaching and support, but choosing an item does not prove that access to it will reinforce a specific behavior. To confirm effectiveness, observe whether access actually increases or maintains the behavior in the relevant setting.

Prepare for an assessment

Before an assessment, identify a varied but manageable set of available, safe, and appropriate options. Ask the person when possible, consult people who know them, and observe what they approach or use in everyday settings.

Make participation accessible by accepting the person’s reliable way of choosing, such as reaching, looking, pointing, speaking, signing, or using a communication device. Check that the person can see and access the options and that the response does not require a skill they do not yet have.

Set consistent procedures: choose the format, define the selection response and any time limit, decide how access after a choice will work, and prepare a data sheet. Use consistent instructions and distinguishable options. Counterbalance or rearrange option positions to reduce location bias.

Explain or demonstrate the procedure as appropriate, but do not force a selection. Honor withdrawal, refusal, or a request to stop, and follow applicable health, dietary, and safety requirements. Do not create deprivation or withhold needed items to increase selection.

Compare options in pairs

In a paired-stimulus assessment, present two options at a time and allow the person to choose one. If the procedure includes access after a choice, provide brief, consistent access to the selected option before presenting the next pair. Across the assessment, pair each option with every other option and counterbalance left–right positions.

Record how often each option is selected and how many times it was available. Calculate its selection percentage as follows:

Options selected more often are ranked as more preferred in this assessment. With $n$ options, a complete set requires $\frac{n(n-1)}{2}$ distinct pairs, so the assessment can take time as the list grows.

Present an array of options

A multiple-stimulus assessment presents several options together in an array and invites a choice. In Multiple stimulus with replacement (MSW), after the person selects an option and receives the planned access, return that option to the array before the next choice. The person can therefore select the same option repeatedly.

In Multiple stimulus without replacement (MSWO), remove the selected option after the planned access and rearrange the remaining options before presenting the next choice. Continue until all options have been selected, the person stops choosing, or the session ends.

Record the order of selection across rounds. In an MSWO, early selections indicate higher relative preference within that session; later selections are made from a smaller set. MSWO can produce a ranking efficiently, while paired-stimulus assessment may be useful when more detailed comparisons are needed.

Observe free engagement

In a free-operant assessment, place several options within reach and allow the person to engage freely with any of them for a defined observation period. Do not require a choice on each trial or remove an option merely because it has been selected. Record engagement with each option, commonly as duration, and compare the results.

This format measures what the person engages with when options are concurrently available, rather than what they select in repeated forced comparisons.

Interpret results cautiously

Summarize the observed choices or engagement and, when useful, arrange options into a relative preference hierarchy, such as higher, middle, and lower within the assessed set. Treat this hierarchy as a snapshot of behavior under the assessment conditions, not as a permanent ranking or a guarantee that an item will work as a reinforcer.

Results can differ by format, context, how options are presented, and how much effort is required to obtain them. If the pattern is unclear, repeat the assessment or try a suitable alternative format.

For example, in an MSWO with a book, bubbles, music, and a puzzle, the person chooses bubbles first, music second, the book third, and the puzzle last. This suggests that bubbles were most preferred among those options in that session. To test whether bubbles are useful in teaching, provide access contingent on a target response and check whether that response improves. If it does not, reconsider the item, the access provided, the task, and the assessment results.

Respond to changing preferences

Preferences can shift with the person’s current interests, setting, available options, recent access, and the activity or task at hand. Reassess periodically and when engagement or learning changes; do not assume that an option preferred previously will remain effective.

Offer meaningful choices during everyday activities where feasible, and observe ongoing assent and engagement. Maintain several possible options rather than relying on one item, and use current evidence—not a past ranking—to guide decisions.

• Potential reinforcer