These answers draw in part from “Technician WORKSHOP #1: You Can Have Whatever You Like: Understanding Preference Assessments and Incorporating Them Into Your Practice” by Rachel Peters, M.S., BCBA (BehaviorLive), and extend it with peer-reviewed research from our library of 27,900+ ABA research articles. Clinical framing, BACB ethics code references, and cross-links below are synthesized by Behaviorist Book Club.
View the original presentation →A preferred item is one the individual selects more readily or approaches more often than alternatives during a preference assessment. A reinforcer is a stimulus whose delivery following a behavior increases the future probability of that behavior under similar conditions. Preference assessment identifies items likely to function as reinforcers, but the reinforcer function can only be confirmed by observing the item's effect on the target behavior in the context of the actual skill program. An item that is highly preferred may still fail to function as a reinforcer if it is delivered after too long a delay, if the individual is satiated, or if the contingency is not clear.
A free operant preference assessment involves making multiple items or activities available in the individual's environment simultaneously and observing which items they approach, interact with, and spend the most time with during an unstructured observation period. It is a naturalistic, low-effort format that provides a snapshot of current preference without requiring structured trial-by-trial administration. Free operant assessments are most useful as a brief daily check at the start of sessions or as an initial screen for identifying candidate items for more structured assessment. Their limitation is that they do not produce a precise rank ordering of preference strength among items.
In an MSWO assessment, all items being assessed are presented simultaneously in an array. The individual is allowed to select one item, which is then removed from the array. The remaining items are rearranged, and the individual selects again. This continues until all items have been selected or a trial limit is reached. The order of selection provides a preference hierarchy: the first item selected is the most preferred, subsequent selections provide decreasing preference rankings. MSWO is more efficient than paired stimulus for generating preference hierarchies when five or more items are being assessed.
Preference is not a fixed characteristic — it changes over time within the same individual due to satiation, changing motivational states, developmental changes, seasonal or contextual variation, and exposure effects. An item that was highly preferred six months ago may be neutral or even aversive now. Conducting preference assessments once and applying the results indefinitely produces reinforcement programs based on outdated information that may no longer reflect the individual's current preferences. Regular reassessment — at minimum quarterly, with brief informal checks at each session — ensures that reinforcement selection reflects current preference.
Satiation is the reduction in reinforcing value of a stimulus following repeated or extended exposure to it. When a client has had unlimited access to a preferred item immediately before a session, or when the same item has been used as the sole reinforcer across many consecutive trials, its effectiveness as a reinforcer decreases. Behavior technicians should monitor for signs of satiation — declining response rates, longer latency to respond, pushing items away after contact — and rotate to alternative reinforcers from the preference hierarchy when satiation is observed. Restricting access to preferred items outside of sessions is a practical antecedent strategy for maintaining reinforcer effectiveness.
Paired stimulus assessments are most appropriate when a precise rank ordering of preference strength among a relatively small number of items (typically three to eight) is needed, when the clinical decision requires clear differentiation between items of similar preference strength, or when the individual's preference is difficult to determine through less structured methods. The limitation of paired stimulus assessments is their administrative burden — the number of trials required increases substantially with the number of items. For larger item sets, MSWO is more efficient while providing comparable hierarchy information.
No. Single stimulus assessments present items individually and record whether the individual approaches or interacts with each item, but they do not present items in competition with one another. The result is a list of items the individual responds to versus items they do not, but not a relative ranking of preference strength among items. Single stimulus assessments are useful for generating a list of candidate items for more structured assessment, for assessing items that cannot be easily presented simultaneously, or for individuals who are overwhelmed by multiple-item arrays. They should not be used when relative preference hierarchy is the clinical question.
Reinforcer rotation involves systematically varying the reinforcers used across trials, programs, or sessions to prevent satiation and maintain reinforcer effectiveness. A behavior technician implementing reinforcer rotation uses the preference hierarchy from a recent assessment to identify multiple items with high preference rankings, then alternates among them rather than using the same item across every trial. Rotation can occur within a session (alternating every few trials) or across sessions (using different top-ranked items in different sessions). The supervising BCBA should specify the rotation schedule in the session protocol based on the client's satiation pattern.
If a client refuses all items during a preference assessment, this is clinically meaningful information that should be reported to the supervising BCBA. Possible explanations include: the assessment is being conducted when the client is ill, hungry, tired, or emotionally dysregulated; none of the items in the assessment set are currently preferred; the assessment format is not appropriate for this individual; or the client is experiencing a period of low motivation that requires clinical attention. The technician should not force interaction with items and should document what was observed and report to the supervising BCBA rather than proceeding to a skill program without adequate reinforcer identification.
Systematic preference assessment reflects respect for the individual's autonomy by allowing them to choose what they find rewarding rather than having practitioners or caregivers decide what should be reinforcing. When an individual consistently selects an item or activity through a preference assessment, that preference should be honored in the reinforcement program — even if the item is unusual or not understood by others — because it reflects the individual's genuine current preference. This connects directly to the broader commitment in ABA to person-centered practice and to the ethical obligation under the BACB Ethics Code (2022) to use positive reinforcement as the foundation of intervention.
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Technician WORKSHOP #1: You Can Have Whatever You Like: Understanding Preference Assessments and Incorporating Them Into Your Practice — Rachel Peters · 0 BACB General CEUs · $0
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All behavior-analytic intervention is individualized. The information on this page is for educational purposes and does not constitute clinical advice. Treatment decisions should be informed by the best available published research, individualized assessment, and obtained with the informed consent of the client or their legal guardian. Behavior analysts are responsible for practicing within the boundaries of their competence and adhering to the BACB Ethics Code for Behavior Analysts.