Introduction to Preference Assessments


  • Define preference assessment
  • Discuss why preference assessments are important
  • Discuss characteristics of preferences
  • Review indirect and direct strategies
  • Review example of structured preference assessments

What is a Preference Assessment?

  • A tool used to systematically identify preferred stimuli that may function as reinforcers for your learner

Why do we Need Preference Assessments?

  • To determine what may be reinforcing to the learner
  • Effective reinforcers increase the likelihood that the learner will engage in the same desired behavior in the future

What do we Know About Preferences?

  • Preferences change over time
  • Preferences change when items are put into competition with other items
  • Preferences change with other environmental influences (things such as your child not having enough sleep, the weather outside, whether or not there is school that day, whether or not there is a fun vacation coming up, being sick, etc.)
  • So, it’s really important to assess preferences so alternatives can be identified as motivation for a particular preference changes over time.
  • Verbal self-report is NOT as reliable as physical choice response
  • It’s important to frequently assess preferences! Because they change. Frequently.

How do you Pick What Might Function as a Reinforcer?

  • Both indirect and direct strategies can be used
    • Caregiver report: a good place to start as they spend the most time with the learner and can help determine which groups of items may function as reinforcers. However, this information cannot be relied upon solely as the caregiver’s ability to predict motivators may not be reliable. But it is a good starting point. That being said, it may be useful, especially if said caregiver bought kiddo something new and they are really interested in it that day and it could be a great motivator!
      • The Reinforcer Assessment for Individuals with Severe Disabilities (RAISD): is a more structured survey for caregivers when assessing a learners preferences
      • The BCBA will determine what method will be used to assess caregiver reporting of a learners preferences
      • The RBT should follow all instructions as set forth by the BCBA
    • Self-report: depends on the ability of the learner, if they are able they may be able to tell you what they want, but be wary self-reporting is not particularly reliable
      • And this can be provided via:
        • Open ended questions like “what do you want to work for” or
        • Closed ended questions by providing a list of choices
        • Asking learns to rank a list in order of most wanted to least
        • This could be a vocal question, written or a survey
    • Free Operant Preference Assessment: free opportunity to observe the learner and see what they prefer, see what they interact with. Here the therapist records the duration of time that the learner interacts with each item that is available. These items and activities are predetermined and the learner is given free access to them.
      • Results in a hierarchy of preference among the presented items
    • Structured Preference Assessment: Conduct an assessment that provides the learner opportunities to indicate their preferences through physical choice responses meaning they will reach for, touch, point at, or in some way indicate their preference

Structured Preference Assessment

In order to assess what functions as a reinforcer for the learner the RBT must conduct regular preference assessments that indicate the preferred reinforcer in that moment.

We will review three types of preference assessments here:

**Note: Prior to the assessment let the learner interact with each item, and prior to beginning each assessment trial, line the items (5-7) up such that they are equidistant from the learner (That way they chose based on preference and not proximity)

  1. Multiple Stimuli Without Replacement (MSWO): Identifying the hierarchy between a set of items presented to a learner. Essentially the learner picks and item, the items are then removed and immediately put back in front of them (minus the chosen item) and they choose from the remaining items. And so on and so forth until all items have been chosen. No items are replaced and this results in a hierarchy.
    • To begin Preference Assessment Line the items up equidistance from the learner
    • Say, “pick one”
    • Allow learner to choose from the array and access that item for 30 seconds
    • Then remove the item from the array
    • Line the remaining items up again equidistant
    • Say, “pick one”
    • Repeat process until no items remain

When do we want to use MSWO?

MSWO is a really good procedure when you are trying to move quickly. There are some limitations to MSWO, the learner must have the ability to scan quickly, or in other words to scan an array of items and then make a choice. It is also a good procedure to use if a child does have scanning abilities and choice-making skills to look and choose between multiple items, rather than only one or two items at at time. If scanning difficulties are present than neither MSWO nor MSW are appropriate preference assessments.

Data Collection: Use a Preference Assessment Data Collection Sheet (Super obvious data here)

Brief MSWO

Exactly the same everything as above except there is only one trial instead of multiple trials. The array is presented 2-5 items. The learner chooses the most preferred item. The end. It should be noted that the brief MSWO is fast enough to be done frequently throughout a therapy session, and allows more time-sensitive information on preference. It should also be noted that it is not a replacement for an occasional full preference assessment (and by occasional that means once or twice daily). Those should be conducted too.

  • Can be done at the beginning of the day
  • Or, the beginning of a lesson or block of discrete trials
  • Or, any time motivation appears to be waning…

Data collection is not necessary every time one conducts a Brief MSWO, however the BCBA may still want data sometimes:

  • A particularly difficult lesson
  • If an individual seems to be suffering from decreased attention, motivation, or overall lower skill acquisition

Use the Including Brief MSWO Data on Discrete Trial Data Sheet, and the data will be fairly clear, strong motivators will show an increase in desired behaviors whereas weak motivators will not

2. Multiple Stimuli With Replacement (MSW): Pretty much identical to MSWO except this time we are replacing the “chosen” preference item back into the array as it is selected. There will be as many trials as there items.

**Note: Prior to the assessment let the learner interact with each item, and prior to beginning each assessment trial line the items (5-7) up such that they are equidistant from the learner (That way they chose based on preference and not proximity)

When do we want to use MSW?

MSW is a really good procedure when you are trying to move quickly. If you want to assess whether one particular item is highly preferred above all others. You don’t necessarily get a hierarchy of preference from this method only if one item is highly preferred above others.

Use the MSW Data Collection Sheet, and the data will be fairly clear, strongest motivator will be selected most frequently from array

3. Paired choice: Paired choice is a particularly good assessment for learners who have difficulties scanning and choosing from multiple items. And it does identify a hierarchy of preference between multiple items.

  • Only two items are presented at any given time


  1. Stimuli are presented in pairs until each stimulus has been presented with every other stimulus
  2. Predetermine the sequence of the pairings
  3. Tell the learner what you are presenting and then ask them to make a choice (e.g., “I have a yo-yo and a book, pick one”)
  4. Hold the stimulus or place on table in front of the learner
  5. Give the individual the item they choose for 30 seconds
  6. If the learner attempts to take both, remove them both and represent them
  7. Repeat until all pairs have been presented

When do we want to use Paired Choice?

When your learner has difficulties scanning and picking from an array and when you have time on your hands because the pairing process is time consuming.

What do you do if your learner does not approach either stimulus within 5 seconds?

  • Remove both stimulus
  • Give the learner access to each (separately) for 5 seconds
  • represent the stimuli following steps 1 & 2
  • If the Learner again avoids both stimulus again remove the stimulus for 5 seconds and represent following steps 1 & 2
  • If the Learner again shows now interest just remove both stimuli and move on to the next pair on the list

Summarizing Your Assessment Data

Graph your data is one way to go.

Either way, just like everything else… the BCBA will determine exactly what data will be collected, how it will be collected, and how it will be summarized

General Comments

  • Preference assessments reliably produce clear results
  • If the learner is not consuming or interacting with the items, then those items are not reinforcers for that individual.
    • If that is the case start over with new items
  • Remember, preferences change. Frequently. Assessments should be conducted frequently to gauge the ever changing preferences.

Learn More…

Skill Repertoire Building Procedures: Natural Environment Training (NET)

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