If a behaviour at home or school has you worried, you want to understand it. A functional behaviour assessment is the careful process that helps you do exactly that. It looks closely at a behaviour to work out why it happens. Once you understand the why, you can build a plan that fits the person. This guide walks you through what a functional behaviour assessment involves, so your family knows what to expect at each step.
What is a functional behaviour assessment?
A functional behaviour assessment (FBA) is a structured process that works out why a behaviour happens, by looking at what comes before it, what the person does and what happens after. It is a core part of positive behaviour support. The findings become the base of a Behaviour Support Plan.
The word “functional” points to the function of behaviour. In plain terms, that means the job the behaviour does for the person. It might help a person escape something hard. It might get attention, or access to something they want. It might meet a sensory need. A behaviour can even be the clearest way a person has to communicate.
The NDIS Quality and Safeguards Commission sets out what it expects from an FBA in its Behaviour Support Assessment, including FBA, Practice Guide (2026).
Why does a functional behaviour assessment matter?
A functional behaviour assessment matters because a plan only fits when it is built on why a behaviour happens. If we only react to what a behaviour looks like, we miss the need underneath. The plan then treats the surface and not the cause. The FBA turns guesswork into evidence.
Under the NDIS, a comprehensive Behaviour Support Plan must be based on a behaviour support assessment, including an FBA. That is set out in the NDIS Commission’s guidance on how to develop behaviour support plans. This is what we mean by our approach: guided by science, driven by care.
What is ABC recording in a functional behaviour assessment?
ABC recording is a simple way to track a behaviour by noting the Antecedent (what happened just before), the Behaviour (what the person did) and the Consequence (what happened straight after). Over time, the pattern in these notes starts to show the function. It sounds technical, but the idea is everyday.
- Antecedent: what happens right before the behaviour. This might be a request, a loud room or a change in routine. These are the triggers.
- Behaviour: what the person actually does, described clearly and without judgement.
- Consequence: what happens right after. This shows us what the behaviour achieves for the person.
ABC recording is one of the most useful things a family can help with. A few plain lines each time is enough.
What happens during a functional behaviour assessment?
A functional behaviour assessment usually moves through 6 steps: referral, background information, interviews, observation, data collection and naming the function. Every family is different, so the pace can shift, but the shape stays the same.
- Referral and getting started. The process begins with a referral. We have a first conversation to understand your concerns and your goals. Any forms we share need your consent, and our privacy policy explains how we handle your information.
- Information gathering. We collect background about the person. This covers their history, health, communication style, strengths and daily routine. Nothing here is about blame. It is about the full picture.
- Interviews with the people who know the person. We talk with family, carers and, where relevant, school or support staff. You see the person across the week, so your view is central to the functional behaviour assessment.
- Observation across settings. We watch how the behaviour plays out in daily life. We do this at home, at school and in the community where we can. The same behaviour can look different in each place, and that tells us a lot.
- Data collection. Throughout, we gather clear data on when a behaviour happens, how often, and what surrounds it. This includes the ABC patterns above.
- Identifying the function. We bring all of it together to name the likely function of the behaviour. This is the answer to the “why”.
What tools are used in a functional behaviour assessment?
A functional behaviour assessment uses structured tools alongside interviews and observation, such as the QABF and a Quality of Life assessment. These tools help the practitioner stay objective. We choose the ones that fit the person, so the mix changes from person to person. Here is what each one is in plain English.
- QABF. This stands for Questions About Behavioral Function. It is a structured questionnaire. It helps sort out whether a behaviour is about escape, attention, access to something, or a sensory need.
- Quality of Life assessment. This looks at how the person is doing across everyday life, such as wellbeing, relationships, choice and taking part in the community. It helps us see strengths to build on, as well as what could be better.
We support people of all ages, from young children through to older adults, and the tools change to suit each person.
How long does a functional behaviour assessment take?
A functional behaviour assessment usually takes several sessions, because it needs interviews, observation in more than one setting and time to collect data. There is no fixed timeframe. Where a regulated restrictive practice is in use, the NDIS (Restrictive Practices and Behaviour Support) Rules 2018 require a comprehensive plan within 6 months of the provider being engaged.
Rushing an assessment risks missing the cause. Gathering enough information, observing across settings and writing up the findings cannot be done in a single visit. We give you an idea of timing once we understand your situation, and we keep you updated at every stage.
What is your family’s role in a functional behaviour assessment?
Your family’s role is to share what you see, take part in interviews and keep simple notes when a behaviour happens. You know the person well. You notice the small changes, the patterns and the triggers that others miss. Your input makes the functional behaviour assessment sharper and the plan more useful.
This is behaviour support as a team effort. If you would like help keeping notes, our free printable resources include charts you can use at home.
What happens after a functional behaviour assessment?
After a functional behaviour assessment, the findings are used to write a Behaviour Support Plan with practical strategies for daily life. The plan focuses on teaching new skills, adjusting the environment and reducing triggers. The aim is to help the person meet their needs in safer, calmer ways. You can read more about what a behaviour support plan is in our related guide.
Where restrictive practices are in place, the plan works towards reducing them and, where possible, removing them over time. As a registered NDIS provider, we follow the NDIS Quality and Safeguards Commission’s rules. We complete the assessment as part of our Behaviour Support Plan work, charged at $252.99 per hour, in line with NDIS pricing arrangements. We confirm your rate at the first consultation and in your service agreement.
Frequently asked questions
What is the difference between an FBA and a behaviour support plan?
An FBA is the assessment that works out why a behaviour happens. A behaviour support plan is what comes next. The plan uses the findings to set out strategies for the person and their supporters. You need the assessment first, because it tells the plan what to focus on.
Who carries out a functional behaviour assessment?
An NDIS behaviour support practitioner carries out the assessment. Our team includes practitioners experienced with complex needs and trauma-informed practice, including Michelle Boyce. Each assessment is led by a practitioner with the right capability for the person’s needs.
Does an FBA only apply to children?
No. A functional behaviour assessment can support a person of any age. We work with children, teenagers, adults and older adults. Behaviour can be understood and supported at any stage of life, and the tools we use change to suit the person.
Where does the functional behaviour assessment take place?
We come to the settings that matter for the person. This usually means home, school or work, and the community. Seeing the behaviour where it happens gives us the clearest understanding. To learn about the wider approach, read about positive behaviour support.
Ready to understand the why?
Understanding a behaviour is the first step towards change. If you are worried about a behaviour at home, school or in the community, a functional behaviour assessment can help you make sense of it. To talk it through, make a referral and our team will call you to talk through the next steps. You can also contact our team with a question.
