How to Conduct a Preference Assessment: A Step by Step Clinical Guide

Reinforcement is the engine of ABA therapy. But reinforcement only works if the reinforcer you are using is something the person you are working with actually wants. A sticker means nothing to a child who does not care about stickers. A verbal well done produces no increase in behaviour for a child who is not motivated by social praise.

This is why preference assessments are not optional in quality ABA practice. They are how you find out what actually motivates your client so that the reinforcement you use in sessions is genuinely effective rather than assumed.

This guide walks you through the four main preference assessment methods, when to use each one, and how to conduct them step by step.

Why Preference Assessments Matter

Before going into the methods, it is worth being clear on what you are actually trying to find out through a preference assessment.

You are not just making a list of things a client likes. You are identifying which specific items, activities or social interactions are motivating enough to function as effective reinforcers in therapy sessions. There is a meaningful difference between something a child enjoys in a general sense and something they will work for consistently in a structured teaching context.

Preferences also change over time. What motivated a child six months ago may have lost its value through repeated access or simply through the child's development and changing interests. Preference assessments should be conducted regularly, not just at the start of a programme, to ensure the reinforcers being used in sessions remain genuinely effective.

Method One: Free Operant Observation

What it is: You observe the client in an environment with multiple items or activities available and record what they naturally gravitate toward without any direction from you.

When to use it: This is the best starting method for a new client, particularly young children or individuals with limited verbal communication. It gives you a naturalistic picture of what the person finds genuinely interesting and engaging when no demands are being placed on them.

How to conduct it step by step:

Set up a space with a variety of items available. Include toys, sensory materials, food items if appropriate, and activities covering different categories. Make sure everything is accessible without the client needing to ask for it.

Allow the client to move freely in the space for five to ten minutes. Do not prompt them toward anything or redirect them away from anything. Your role is purely to observe.

Record which items they approach, how long they spend with each one, and whether they return to any items after moving away. Items that are approached quickly, engaged with for longer, and returned to repeatedly are your highest preference items.

Use this information to build an initial reinforcer menu for the client.

Method Two: Single Stimulus Presentation

What it is: You present one item at a time and record whether the client approaches or engages with it.

When to use it: This method is useful for clients who become overwhelmed when multiple items are presented simultaneously, or for systematically testing a specific list of potential reinforcers.

How to conduct it step by step:

Prepare a list of items you want to assess. Present each item individually to the client for a set period, typically around thirty seconds. Record whether they approach the item, engage with it, or avoid or ignore it.

Remove each item before presenting the next one. Work through your entire list systematically.

Items that consistently produce approach and engagement across multiple presentations are your preferred items. Items that are consistently ignored or avoided are not effective reinforcers for this client at this time.

Method Three: Paired Stimulus or Forced Choice

What it is: You present two items simultaneously and ask the client to choose between them. By running multiple pairs, you generate a ranked hierarchy of preferences.

When to use it: This method is one of the most commonly used in ABA practice because it produces a clear ranked preference hierarchy. It works well for clients who can make a choice between two options reliably.

How to conduct it step by step:

Identify the items you want to include in the assessment, typically six to eight items to start.

Present two items at a time, side by side, equidistant from the client. Allow the client to choose one. Record which item was chosen. Remove both items briefly before presenting the next pair.

Systematically pair every item with every other item on your list so that each item appears an equal number of times. Record every choice made.

Calculate the percentage of times each item was chosen out of the total number of times it was presented. Items with the highest selection percentage are your highest preference items.

Method Four: Multiple Stimulus Without Replacement

What it is: You present an array of items simultaneously. The client chooses one, which is removed. The remaining items are rearranged and presented again. This continues until all items have been chosen or the client stops engaging.

When to use it: This method is efficient when you want to assess multiple items quickly and produces a ranked preference hierarchy in a single assessment session. It is particularly useful for clients who are able to choose from several options.

How to conduct it step by step:

Arrange five to seven items in a line or arc in front of the client. Allow them to choose one. Record which item was chosen and note its position in the array.

Remove the chosen item. Rearrange the remaining items so position is not a confounding factor. Present the array again and allow the client to choose again.

Continue until all items have been chosen or the client disengages from the task. The order in which items were chosen gives you your preference hierarchy, with the first item chosen being the highest preference.

Recording and Using Your Results

After any preference assessment, organise your results into a clear hierarchy from highest to lowest preference. Share these results with your supervising clinician and update the client's reinforcer menu accordingly.

Use your highest preference items as reinforcers for the most demanding targets in the treatment plan. Reserve medium preference items for less demanding tasks. Rotate reinforcers across sessions to prevent satiation, which is the loss of a reinforcer's effectiveness through repeated access.

Reassess preferences regularly, at minimum every few months, and more frequently if you notice that previously effective reinforcers are losing their motivational value during sessions.

How NeuroCore Builds This Into Clinical Practice

At NeuroCore, preference assessments are a standard part of every initial clinical assessment and are conducted regularly throughout every programme. Understanding what genuinely motivates each individual client is foundational to everything else we do.

Visit our IBT and ABAT Training page to learn more or enrol now and find out when our next live sessions are scheduled.