WTF: What's the Function?
- Maria Esguerra
- Jun 18
- 4 min read
Updated: Jun 20
Understanding Behaviour Through Functional Behaviour Assessment (FBA)
When someone displays a challenging behaviour, it's natural to want to jump in and stop it. Many carers or staff—often with the best intentions—say, “Let’s just make this behaviour stop.” But without understanding why the behaviour is happening, any intervention risks being ineffective—or even harmful.
As behaviour support practitioners, our job isn’t just to stop behaviours. It’s to understand them. That begins with a simple but powerful question:
WTF – What’s the Function?
This is the heart of Functional Behaviour Assessment (FBA)—a core part of the Positive Behaviour Support (PBS) approach. Far from a tick-box exercise, a well-done FBA forms the foundation of meaningful, respectful, and person-centred support. It’s also a requirement under the NDIS Commission’s Behaviour Support rules.
What is a Functional Behaviour Assessment (FBA)?
An FBA looks at the function a behaviour serves for a person in the context of their environment. Behaviour doesn’t happen in a vacuum—every action, no matter how complex or disruptive, is a form of communication.
According to the NDIS Commission, an FBA is “the process for determining and understanding the function or purpose behind a person’s behaviour,” using data, observations, and input from the person and their circle of support. Importantly, it’s just one part of a larger behaviour support assessment that also includes biopsychosocial, environmental, and trauma-informed factors.
A strong FBA includes:
A clear description of the behaviour (frequency, duration, intensity)
Identification of environmental triggers (antecedents)
Observation of consequences that maintain the behaviour
A hypothesis about why the behaviour occurs
This aligns with the functional model: Setting events, Antecedents, Behaviour, and Consequences—helping us move from guesswork to informed, person-centred strategy.
Why Guessing Doesn’t Work: Real-World Lessons
After 15+ years in the disability sector (and over two decades as a carer), I’ve seen the consequences of bypassing FBA too many times. Well-meaning teams jump into managing behaviours without truly understanding them—and the outcomes can be tragic, frustrating, or both.
Here are just a few real-life scenarios based on cases I’ve encountered:
👉 Misreading Demand Avoidance as “Bad Behaviour”
A boy returning to school after holidays was withdrawn and non-compliant. Staff assumed he was avoiding demands—so they handed him a movie to keep him quiet. In truth, he was anxious and overwhelmed. What he needed was reassurance, connection, and a calm presence. When the support changed, so did the behaviour.
👉 Masking Pain with Medication
A young woman labelled with a “delusional disorder” was heavily medicated with antipsychotics. Her distress was interpreted as psychiatric. Only after a thorough review was it discovered she had a serious untreated medical issue requiring surgery. Her behaviour wasn’t delusional—it was her only way of expressing pain.
👉 “He Hates Transitions”—Or Does He?
One man was described as struggling with change. But closer observation revealed his behaviour was triggered not by the transition itself, but by how staff were speaking about him—often in front of him. He was trying to communicate discomfort with disrespect. He didn’t need more “transition strategies.” He needed dignity.
These cases highlight the danger of assumptions. Without FBA, we risk treating symptoms instead of causes—and that can lead to harmful, ineffective, or even traumatising responses.
The Five Key Behaviour Functions
Most behaviours of concern fall into one or more of the following categories:
Escape or Avoidance – To avoid a demand or activity
Attention Seeking – To gain interaction or acknowledgement
Access to Tangibles – To get something (items, food, activities)
Sensory Stimulation – To seek or avoid certain sensory input
Physical Discomfort – To express pain, illness, or discomfort
But behaviours often reflect more nuanced messages:
“I’m lonely”
“I’m bored”
“I want control”
“I’m not safe here”
“I want a normal life”
When we understand the true function, we can teach replacement behaviours and modify environments to meet the person’s needs safely and respectfully.
How FBA is Conducted (According to the NDIS Commission)
An FBA must be person-centred, collaborative, and holistic. Under the NDIS framework, this means:
Indirect methods – interviews, questionnaires, conversations with people who know the person well
Direct observation – watching the behaviour in real-life situations
Active involvement of the person – using supported decision-making, visuals, or assistive communication tools
Qualified practitioners only – FBAs must be conducted by registered behaviour support practitioners approved by the NDIS Commission
All this information is integrated into a clear, evidence-based hypothesis and informs the design of the Behaviour Support Plan (BSP).
Why It Matters – Ethically, Legally, and Practically
The NDIS Commission is clear: comprehensive behaviour assessments—including FBA—are not optional. They’re required to:
Protect the rights of people with disability
Guide the reduction of restrictive practices
Ensure interventions are evidence-based, proactive, and person-centred
Prevent harm, misdiagnosis, and over-medication
Without an FBA, interventions often rely on guesswork. This leads to:
Ineffective strategies
Increased distress
Erosion of trust
Ethical and legal risk
Wasted time, money, and staff effort
The Bigger Picture: Trauma, Risk, and Mental Health
A good FBA also considers:
Trauma history – Many behaviours stem from past trauma. Support must be safe, predictable, and nurturing.
Mental health and dual diagnosis – People with disability often experience mental health challenges, and these must be assessed carefully and holistically.
Risk management – FBAs must appraise risk factors and ensure interim safety measures while strategies are developed.
Final Thoughts: The Power of Asking Why
Functional Behaviour Assessment is more than a tool—it’s a mindset. It shifts us from reacting to understanding. From controlling behaviour to supporting the person. It’s what the NDIS framework demands—and what people deserve.
So next time you’re faced with a behaviour of concern, don’t jump to intervention.
Start by asking:
WTF – What’s The Function?
Because when we stop guessing and start listening, everything changes.
References:
Policy Guidance - Behaviour Support Assessment including Functional Behaviour Assessment