Understanding Functional Behaviour Assessments (FBA)

When families first hear the term Functional Behaviour Assessment (FBA), it can sound clinical, overwhelming, or even intimidating. Many parents and carers worry that it means their child is being “assessed” or judged. In reality, an FBA is not about labelling a person — it’s about understanding behaviour so we can better support the individual. 

What Is a Functional Behaviour Assessment?

An FBA is a systematic, evidence-based process for collecting and analysing information to understand why behaviour occurs and what function (purpose) it serves for the person. By looking at patterns over time, we can use this information to make meaningful, personalised support decisions.

In the field of behaviour science, FBAs are considered a cornerstone of effective Positive Behaviour Support because they guide intervention design based on the function of behaviour rather than assumptions. 

What Happens During an FBA?

An FBA isn’t a test; it’s a collaborative and supportive process. It usually includes:

• Conversations with parents/carers, educators, and other support people
• Clarifying exactly what the behaviour looks like in observable terms
• Systematically collecting observation data (what happened before, during, and after)
• Looking for patterns in settings, triggers, and responses
• Developing a hypothesis about the behaviour’s function

These steps help us move beyond guesswork toward data-informed support decisions.

What Information Does an FBA Provide?

An FBA helps us understand:

1. Triggers: What tends to happen just before the behaviour?
2. The Behaviour: What exactly is happening — clearly described and observable?
3. Function: What purpose does the behaviour serve (e.g., to access attention, avoid tasks, sensory regulation)?
4. Skill Gaps: What skills might be missing — like communication or regulation — that could be taught instead?

Because the strategies in a Behaviour Support Plan are linked directly to the function
identified in the FBA, research shows that interventions based on functional assessment data are more effective than those that aren’t. 

Why Do We Need an FBA?

Without an FBA, behaviour planning often becomes trial and error — strategies may be chosen based on what seems logical rather than what the data indicates. This can lead to frustration and inconsistent outcomes, and sometimes the behaviour continues or even gets worse.

By contrast, when interventions are developed from functional assessment information:

• Strategies are tailored to the person and context
• Supports focus on skill-building and prevention
• Reactive or punitive responses are reduced

This leads to more sustainable changes, better quality of life, and more confidence for families and practitioners alike. 

How an FBA Helps Behaviour Support

Once an FBA is completed, the information gathered directly informs a Behaviour Support Plan that will include:

• Preventative strategies to reduce triggers
• Replacement skills that meet the same function as the behaviour
• Clear guidelines for responses across settings
• Data collection to monitor progress and adjust supports

This means support becomes proactive rather than reactive — we teach skills before crisis moments occur. 

Reassurance for Families

An FBA is not about blame or saying someone is “wrong.” It’s about partnership — bringing together family insight, observational data, and professional expertise to build understanding and support that actually works.

At its core, an FBA helps everyone answer the simple yet powerful question:

“What does this behaviour mean for this person in this context?”

When we understand that, we can design supports that help the individual feel understood, supported, and equipped for success.