Functional Behavior Assessment (FBA) is a systematic process for identifying the variables that maintain problem behavior. It’s a core competency tested on the BCBA exam and essential for ethical, effective intervention planning.
What is an FBA?
An FBA identifies the function of behavior — the reason it occurs. All behavior serves a purpose, typically categorized into four functions:
- Attention — behavior maintained by social interaction
- Escape/Avoidance — behavior maintained by removal of demands or aversive stimuli
- Access to Tangibles — behavior maintained by obtaining preferred items or activities
- Automatic Reinforcement — behavior maintained by sensory consequences
The Three Levels of Assessment
Level 1: Indirect Assessment
- Interviews with caregivers, teachers, or staff
- Rating scales and checklists (e.g., MAS, FAST)
- Record reviews
Limitations: Based on recall, subject to bias
Level 2: Descriptive Assessment
- Direct observation in natural settings
- ABC (Antecedent-Behavior-Consequence) data collection
- Scatter plots to identify temporal patterns
Limitations: Correlational, cannot establish causation
Level 3: Functional Analysis (Experimental)
- Systematic manipulation of antecedents and consequences
- Conditions: attention, demand, alone/ignore, play/control
- Provides strongest evidence of function
Limitations: Requires controlled conditions, ethical considerations
Writing an FBA Report
A complete FBA report should include:
- Operational definition of the target behavior
- Summary of indirect assessment results
- Descriptive assessment data and patterns
- Functional analysis results (if conducted)
- Hypothesized function(s)
- Recommendations for intervention
Exam Application
On the BCBA exam, expect questions about:
- When to use each level of assessment
- Interpreting functional analysis graphs
- Selecting interventions based on function
- Ethical considerations in conducting FBAs