A Functional Behaviour Assessment (FBA), also spelled Functional Behavior Assessment in the United States, is a structured process for understanding behaviour of concern: what is happening, the circumstances in which it occurs, what may be contributing to it, and the function or purpose the behaviour may serve for the individual.
Rather than simply asking, “How do we stop this behaviour?”, an FBA asks a more useful question: “Why might this behaviour be occurring, and what does the person need?”
This distinction is central to Positive Behaviour Support (PBS). A well-conducted Functional Behaviour Assessment brings together information from different sources to identify patterns, develop a functional hypothesis and inform individualised strategies that address the reasons for the behaviour.
This guide takes you through seven practical steps:
- Identify and define the behaviour of concern
- Gather information and behaviour data
- Analyse the information and identify patterns
- Develop a functional hypothesis
- Develop Positive Behaviour Support strategies
- Implement the strategies
- Monitor, evaluate and review
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You’re doing important work. That’s why we built the Behaviour Help App — to make it easier to track behaviour trends, identify patterns, and develop meaningful, person-centred strategies.
What Is a Functional Behaviour Assessment (FBA)?
A Functional Behaviour Assessment is more than an ABC behaviour chart or a single observation. It is a process of gathering and analysing information to develop an evidence-informed understanding of when, where and why behaviour occurs.
Depending on the individual and setting, information may come from:
- direct observation
- ABC (Antecedent–Behaviour–Consequence) data
- behaviour frequency, duration or intensity data
- interviews with the individual and people who know them well
- questionnaires and assessment tools
- previous reports and records
- communication, health and developmental information
- environmental and contextual information
- the individual’s strengths, preferences, needs and quality-of-life priorities
The purpose is not simply to attach a label or function to behaviour. The assessment should help us understand the person and the context sufficiently well to develop meaningful, practical and person-centred support.
Functional Behaviour Assessment Is a Collaborative Process
Where possible, the individual should be central to the assessment process. Other contributors will vary according to the person’s circumstances and may include:
- Family members and carers, who provide valuable insight into the individual’s behaviour across different settings and times.
- Behaviour Support Practitioners.
- Behaviour Analysts or BCBAs (Board Certified Behaviour Analysts), who have specialised training in conducting FBAs.
- Psychologists, including school and clinical psychologists with experience in behaviour assessment and intervention.
- Teachers and educators, particularly those with training in special education and behaviour management.
- Speech pathologists/speech and language therapists, especially where the behaviour is related to communication difficulties.
- Occupational therapists, particularly when sensory issues are thought to contribute to the behaviour.
- Disability support workers.
- Other allied health professionals.
- Service providers.
Each person may hold a different piece of the picture. For example, a behaviour may occur frequently at school but rarely at home, or it may be more likely during particular activities, transitions, interactions or environmental conditions. Bringing these perspectives together can provide a much richer understanding than relying on a single observation or source of information.
The 7 Steps of a Functional Behaviour Assessment
Step 1: Define the Behaviour of Concern
The first step is to clearly identify what behaviour is being assessed.
Terms such as aggressive, disruptive, non-compliant, defiant or challenging can mean very different things to different people. Instead, describe the behaviour in observable and measurable terms.
Ask:
- What does the person actually do?
- What would someone see or hear?
- Where does the behaviour begin and end?
- How frequently does it occur?
- How long does it last?
- Does its intensity vary?
- Are several different behaviours being grouped together?
For example, rather than “Sam becomes aggressive”, a clearer description might be: “Sam hits another person with an open or closed hand, kicks towards another person’s body, or throws objects towards another person.”
A clear operational definition means that different people collecting information are identifying and recording the same behaviour. It also establishes a baseline against which future change can be evaluated.
Why this step matters
If a behaviour is poorly defined, the data collected about it will also be unreliable. Before trying to determine why a behaviour occurs, everyone involved needs to be clear about which behaviour they are actually investigating.
Example behaviour of concern definition
Target behaviour: ‘Property Damage/Destruction’.
Operationally defined behaviour: Sam will gouge a surface (wall, table) with a screwdriver with such force that it creates a hole in the surface.
Step 2: Collect FBA Data – Interviews, Observations and ABC Behaviour Charts
Once the behaviour has been clearly defined, the next step is to gather information about when, where and under what circumstances it occurs – and when it does not occur.
One commonly used method is ABC behaviour data collection.
- A – antecedent
- B – behaviour
- C – consequence
Antecedent
The antecedent is what happened immediately before the behaviour.
- What was happening?
- Where was the person?
- Who was present?
- What activity was occurring?
- Was something requested, changed, delayed, stopped or unavailable?
- Was there a transition?
- What was happening in the environment?
Behaviour
Record exactly what the person did. Avoid interpretations such as “He was trying to manipulate staff.” Instead, record what could actually be observed, for example: “He asked for the item four times, raised his voice and pushed the chair away from the table.”
Consequence
The consequence is what happened immediately after the behaviour.
- How did other people respond?
- Did an activity stop?
- Was a demand removed or delayed?
- Did someone approach or move away?
- Did the person gain access to something?
- Did the environment change?
A consequence does not necessarily mean a punishment. In behavioural assessment, it simply describes what followed the behaviour.
Look beyond the immediate ABC
ABC information is valuable, but a comprehensive FBA should not be limited to what happened immediately before and after an incident.
Broader factors may influence the likelihood of behaviour, including:
- communication needs
- pain, discomfort or health factors
- sleep and fatigue
- sensory experiences
- predictability and change
- relationships
- previous experiences
- demands and expectations
- opportunities for choice and control
- emotional regulation
- skills and support needs
- broader environmental or social circumstances
Information should therefore be gathered from multiple sources wherever possible rather than relying on one incident or one person’s interpretation. In addition to direct observation, it can help to gather supporting information from others who know the individual well – interview teachers, family members or friends, and look for past records to see whether this kind of behaviour has occurred before.
Step 3: Analyse Behaviour Data and Identify Patterns
Collecting data is only useful if we then analyse what it is telling us. Look across observations, interviews, records and behaviour data for recurring patterns.
Ask:
- Does the behaviour occur more often during particular activities?
- Are particular demands, interactions or transitions commonly present?
- Does it occur more frequently with particular people or in particular environments?
- Are fatigue, discomfort, sensory load or other setting events relevant?
- What typically happens immediately afterwards?
- Are there situations in which the behaviour would normally be expected but does not occur?
- What is different about those situations?
Consider the example of Sam. Suppose the data shows that Sam is frequently tired and overwhelmed when he arrives home after school. On days when he can have a snack, spend some time alone and listen to music, he generally transitions successfully into his afternoon.
When he is immediately asked to complete chores, prepare for another activity or engage socially, behaviour of concern is more likely to occur. If the behaviour results in people withdrawing their requests and giving Sam space, this provides further information.
The pattern may suggest that the behaviour is related to escaping or delaying interaction or demands at a time when Sam needs reduced demands and an opportunity to regulate. That is much more informative than concluding that Sam simply “doesn’t like chores”.
Read the full guide to analysing behaviour tracking data.
Step 4: Develop a Functional Behaviour Hypothesis
Once sufficient information has been gathered and patterns have been identified, the next step is to develop a functional hypothesis.
A functional hypothesis is an evidence-informed explanation of the circumstances in which the behaviour is likely to occur and what the behaviour may achieve or communicate for the person.
Functions commonly considered within behavioural assessment include:
- gaining social interaction or attention
- gaining access to an item, activity or experience
- escaping, avoiding or delaying a demand, activity or situation
- obtaining or avoiding particular sensory experiences
However, human behaviour is complex. A behaviour should not automatically be assigned to one of these categories simply because it appears to fit. There may be multiple contributing factors or functions, and the available information may initially support only a preliminary hypothesis.
Here is an example of a student in class being disruptive. Jacob’s behaviour is concerning and disruptive but with some analysis and some hypothesising, the school identifies the underlying cause:
Jacob bangs his feet on the floor during independent reading time in the classroom (the antecedents). The more his teacher tells him to quiet his feet the louder he bangs them and the more he distracts his classmates (the consequences). After this behaviour continues for the first few months of school, his teacher is feeling stuck with how to respond and requests an FBA. The school does an FBA and learns that Jacob does not get attention from important people when he reads quietly. As soon as he starts banging his feet, his teacher (who he likes) and his classmates start paying attention to him and he gets to avoid doing his reading which he finds boring.
Applying the same approach to Sam: “When Sam arrives home from school tired and is immediately presented with additional demands or social interaction, he is more likely to engage in behaviour of concern. This behaviour is frequently followed by demands being removed and Sam being given space. The available information suggests the behaviour may function, at least in part, to escape or delay demands and interaction when Sam is fatigued and requires time to regulate.”
The hypothesis should remain open to review as further information becomes available.
Step 5: Use the FBA to Develop Positive Behaviour Support Strategies
The information gathered through the FBA should now guide intervention. This is where Functional Behaviour Assessment connects directly with Positive Behaviour Support.
Rather than selecting generic behaviour-management strategies, support should address the factors identified through the assessment.
Supportive Environments
Consider strategies relating to the physical and sensory environment, predictability, access and other environmental factors identified through the FBA.
Supportive Activities
Consider task demands, difficulty, pacing, duration, meaningful participation, interests, choice and the level of assistance required.
Supportive Interactions
Consider communication, language complexity, tone, pace, processing time, expectations, autonomy and how supporters respond to the person.
Increase predictability and understanding
Consider whether the individual would benefit from clearer information, preparation for change, visual supports or other communication strategies.
Increase choice and control
Provide meaningful opportunities for the person to make choices, communicate preferences and influence what happens to them.
Support communication
Consider whether the person has an effective and accessible way to communicate needs such as help, break, stop, more time, finished, discomfort, or wanting or not wanting something.
Build useful skills
Consider skills that could increase the person’s independence, participation, communication, self-advocacy or ability to manage difficult situations.
Plan how others respond
Everyone supporting the person should understand how to respond to early signs of distress, escalation and behaviour of concern in ways that prioritise safety, dignity and de-escalation.
The goal is not simply to suppress behaviour. The goal is to use our understanding of why the behaviour occurs to create conditions in which the person has less need to use the behaviour and greater access to effective, acceptable ways of meeting their needs.
Step 6: Implement the Positive Behaviour Support Plan
Even an excellent assessment and support plan will have limited impact if the strategies cannot be implemented effectively. As with the identification of the behaviour of concern and the assessment itself, implementation is a team effort among parents, caregivers and teachers.
Everyone involved should understand:
- what strategies are being used
- why they are being used
- when they should be used
- how the individual communicates
- how to recognise early indicators of distress
- how to respond consistently and safely
- what information needs to be recorded
Consistency does not mean that everyone must respond mechanically or identically. Support should remain responsive to the individual, the context and their needs. What matters is that the underlying approach and agreed strategies are understood and implemented as intended.
Training, coaching, modelling and regular communication may therefore be important parts of implementation. Maintaining a consistent approach across settings – such as at home and at school – is key to giving the individual clear expectations and boundaries. Keep detailed notes and document how the plan is being implemented, continuing to observe and record as in Step 2.
Step 7: Monitor Behaviour Data, Evaluate Outcomes and Review
Functional Behaviour Assessment and Positive Behaviour Support should be ongoing processes rather than documents that are completed and then filed away.
Continue gathering relevant information after strategies are introduced. Consider:
- Is the behaviour occurring less frequently?
- Has its duration or intensity changed?
- Are risks reducing?
- Are preventative strategies working?
- Is the individual using new communication or coping skills?
- Is participation increasing?
- Are strategies practical for the people implementing them?
- Are there unintended effects?
Most importantly, is the person’s quality of life improving?
A reduction in behaviour of concern is only one potential outcome. Meaningful outcomes may also include greater autonomy, participation, communication, choice, relationships, safety, wellbeing and access to valued activities.
If the expected changes are not occurring, return to the assessment. The hypothesis may need refinement, additional information may be required, or the strategies themselves may need to change. Hold meetings with your collaborators to discuss progress and any challenges, and be prepared to make adjustments as you go along.
Functional Behaviour Assessment Template: What Should It Include?
A Functional Behaviour Assessment template can help organise the assessment, but the quality of an FBA depends on the information gathered and the analysis undertaken rather than the form itself.
A useful FBA template may include:
- information about the individual, their strengths, preferences and communication
- clear operational definitions of behaviours of concern
- frequency, duration and/or intensity information where relevant
- setting events and broader contextual factors
- antecedents and triggers
- consequences and responses
- ABC behaviour data
- information from interviews, observations, records and assessment tools
- analysis of recurring patterns
- a functional behaviour hypothesis
- identified evidence gaps or alternative explanations where relevant
- links between assessment findings and Positive Behaviour Support strategies
- a process for monitoring and review
ABC Behaviour Charts and FBA Data Collection
ABC behaviour charts are commonly used during Functional Behaviour Assessment because they provide a structured way to record what happened before, during and after an occurrence of behaviour.
However, an ABC chart is not an FBA on its own. A comprehensive assessment draws together multiple sources of information and looks across repeated observations for patterns. Behaviour data may also include frequency, duration, intensity, scatterplot or contextual information depending on the behaviour and the purpose of the assessment.
The important step is not simply collecting more data. It is collecting relevant information and using it to develop a more accurate understanding of the person and their behaviour.
From Functional Behaviour Assessment to Positive Behaviour Support Plan
Templates, ABC behaviour charts and behaviour data sheets can be extremely useful tools within a Functional Behaviour Assessment. The difficulty for practitioners is that a complete FBA often involves much more than one form.
Information may be spread across interview notes, questionnaires, reports, ABC charts, behaviour data, spreadsheets, graphs, FBA documents and Positive Behaviour Support Plans.
This can make it difficult to maintain a clear pathway from information gathering → behaviour data → analysis → functional hypothesis → Positive Behaviour Support strategies → implementation → review.
For practitioners completing Functional Behaviour Assessments regularly, Behaviour Help provides a structured platform for bringing these parts of the process together. Rather than completing an FBA across separate Word documents, forms, spreadsheets and data files, Behaviour Help supports the process from gathering and organising assessment information and behaviour data through to analysis, Positive Behaviour Support strategies and ongoing monitoring.
Frequently Asked Questions About Functional Behaviour Assessment
What is the purpose of a Functional Behaviour Assessment?
The purpose of an FBA is to develop an evidence-informed understanding of why behaviour occurs so that support can address the person’s needs and the factors contributing to the behaviour, rather than simply responding to the behaviour itself.
What information is included in a Functional Behaviour Assessment?
This varies according to the individual and context but may include operational definitions of behaviours, interviews, direct observations, ABC data, frequency, duration or intensity data, setting events, triggers, consequences, communication and environmental information, assessment tools, analysis of patterns and a functional hypothesis.
What is ABC data in a Functional Behaviour Assessment?
ABC stands for Antecedent, Behaviour and Consequence. It records what occurred immediately before a behaviour, the observable behaviour itself and what happened immediately afterwards. Looking across multiple ABC observations can help identify recurring patterns.
Is an ABC chart the same as a Functional Behaviour Assessment?
No. ABC data is one source of information that may contribute to an FBA. A comprehensive FBA generally draws upon multiple sources of information and requires analysis and interpretation rather than relying on an ABC chart alone.
What is a functional hypothesis?
A functional hypothesis summarises the circumstances associated with a behaviour and the function or outcome the behaviour may serve for the individual. It should be based on the available assessment evidence and reviewed as further information becomes available.
How does an FBA inform a Positive Behaviour Support Plan?
The FBA provides the rationale for the strategies within a Positive Behaviour Support Plan. Understanding the circumstances and likely function of behaviour allows strategies to focus on prevention, environmental support, communication, skill development, quality of life and safe, appropriate responses rather than relying on generic behaviour-management strategies.
Introducting...The Behaviour Help App
Your All-in-One Platform for FBAs and PBS Plans
You’re doing important work. That’s why we built the Behaviour Help App — to make it easier to track behaviour trends, identify patterns, and develop meaningful, person-centred strategies.
Final Thoughts
A Functional Behaviour Assessment is not simply a form to complete or a way of categorising behaviour. It is a structured process for developing a better understanding of the relationship between the person, their environment, their needs and their behaviour.
The seven steps provide a practical framework: Define → Gather → Analyse → Hypothesise → Plan → Implement → Evaluate.
When these steps are completed thoughtfully and collaboratively, the result should be more than a reduction in behaviour of concern. A good FBA should lead to support that is more individualised, preventative, respectful and meaningful – and ultimately contributes to improved quality of life. Whether you are a teacher, therapist, or caregiver, understanding these seven steps can empower you to conduct FBAs that make a significant difference in the lives of those you work with.