Functional Behaviour Assessment: A Scientific Guide to Understanding and Addressing Challenging Behaviours

Understanding the underlying reasons behind challenging behaviours is essential for effective support, particularly in educational and therapeutic settings. A Functional Behaviour Assessment (FBA) is a data-driven, evidence-based process designed to identify the purpose or function behind specific behaviours. By identifying the antecedents, behaviours, and consequences (the ABCs), FBA empowers educators, parents, and clinicians to develop proactive, individualised support strategies that target the root cause rather than merely reacting to the surface-level behaviour.

What Is a Functional Behaviour Assessment?

A Functional Behaviour Assessment is a systematic process used to determine the underlying function of behaviour. Instead of focusing solely on what the behaviour looks like, FBA aims to understand why it occurs. Common functions include:

• Attention-seeking

• Escape or avoidance

• Access to tangibles

• Sensory stimulation (automatic reinforcement)

Each behaviour serves a purpose for the individual. By uncovering this, support plans can be tailored to teach alternative skills that meet the same need in a socially appropriate way.

Purpose and Benefits of FBA FBAs play a critical role in developing Behaviour Support Plans (BSPs). Understanding the function allows for:

• Targeted interventions

• Improved learning and participation

• Reduction of restrictive practices

• Better collaboration across professionals and families

In Australia, FBAs are also essential in meeting NDIS behaviour support compliance and ethical practice standards. Learn more about Positive Behaviour Support with NDIS.

Types of Functional Behaviour Assessments.

There are four recognised levels of FBA, each increasing in complexity and precision:

1. Indirect FBA (e.g., interviews and questionnaires like the QABF or MAS):

   • Strengths: Quick and cost-effective.

   • Limitations: Subjective and less reliable when used alone.

2. Descriptive Assessment (ABC data, scatterplots, observation checklists):

   • Involves direct observation in natural settings.

   • Helps identify patterns but not causality.

3. Functional Analysis Screening Tool (FAST):

   • A structured tool that guides hypothesis development.

   • Often used in conjunction with indirect and descriptive assessments.

4. Functional Analysis (FA):

   • The gold standard for determining behaviour function.

   • Involves manipulating antecedents and consequences in a controlled way.

   • Types of FA include:

     • Multielement design: Tests multiple conditions (attention, escape, alone, control).

     • Trial-based FA: Uses brief sessions embedded in daily routines.

     • Latency-based FA: Measures time to onset of behaviour after condition change.

   • Limitations: Time-consuming, requires expertise, and may not be appropriate for high-risk behaviours without safeguards.

Step-by-Step Process of FBA

1. Identify and define the behaviour clearly and objectively.

2. Gather baseline data through ABC charts, scatterplots, or interval recording.

3. Interview stakeholders (e.g., family, educators, therapists) to gather insights.

4. Analyse patterns to hypothesise the function of the behaviour.

5. Test the hypothesis, where safe and appropriate, through structured observation or Functional Analysis.

6. Develop a Behaviour Support Plan, including:

   • Skill replacement strategies

   • Environmental modifications

   • Reinforcement systems

   • Response strategies for unsafe behaviour

7. Monitor and review regularly with ongoing data collection and stakeholder feedback.

Data Collection Tools

• ABC Data Sheets: Track Antecedent-Behaviour-Consequence sequences.

• Scatterplots: Reveal temporal patterns in behaviour.

• Frequency and duration charts: Show intensity and occurrence trends.

• Standardised tools: QABF (Questions About Behaviour Function), MAS (Motivation Assessment Scale), FAST.

How FBA Informs Behaviour Support

Once the function is confirmed, strategies can be designed to:

• Teach appropriate replacement behaviours that serve the same function.

• Modify the environment to reduce triggers.

• Reinforce positive behaviour.

• Fade reinforcement gradually to encourage independence.

For example, if a student throws objects to escape tasks, teaching them to request a break appropriately can replace the behaviour. Reinforcing this request and providing support gradually builds independence and reduces disruptive episodes.

Challenges and Ethical Considerations FBA can be time-intensive, and when conducted poorly or rushed, may lead to incorrect conclusions. Ethical practice involves:

• Informed consent

• Multidisciplinary input

• Culturally responsive approaches

• Avoiding assumptions based on diagnostic labels

Professionals conducting FBAs should be trained in behavioural analysis or under appropriate supervision. In Australia, practitioners delivering Specialist Behaviour Support must meet NDIS Quality and Safeguards Commission requirements.

Further Learning and Resources

• Association for Behaviour Analysis International

• NDIS Behaviour Support Provider Requirements

• Functional Assessment Toolkit by PBIS.org

Conclusion

Functional Behaviour Assessment is more than a tool—it’s a lens for understanding human behaviour in context. By identifying the function of behaviour, we empower teams to develop compassionate, individualised interventions that foster lasting, meaningful change. Whether you’re a clinician, educator, or parent, investing in high-quality FBA can dramatically improve the quality of support for individuals facing behavioural challenges.

Please contact us a Freedom Therapy Services where we can conduct functional behaviour assessments by one of our psychologists or behaviour support practitioners.