Use when conducting or writing up a Functional Behavior Assessment (FBA) — covers indirect, descriptive, and experimental methods, data integration, function statement writing, and report generation.
A Functional Behavior Assessment is a systematic process for identifying the environmental variables that reliably predict and maintain problem behavior. Under IDEA (2004), an FBA is mandated when a student with a disability faces disciplinary removal exceeding 10 school days or when the behavior is determined to be a manifestation of the student's disability. Beyond legal mandate, FBA is the ethical and empirical foundation for any function-based intervention.
The goal is never simply to describe the topography of behavior — it is to identify the function: the reinforcement contingency maintaining the behavior. Without functional understanding, intervention is guesswork.
Indirect methods gather information through interviews and rating scales without direct observation. They are efficient for generating initial hypotheses but are insufficient as sole data sources.
Structured Rating Scales:
Open-Ended Interviews:
Conduct with all relevant stakeholders (caregivers, teachers, direct-care staff, the individual when possible). Ask:
Descriptive methods involve direct observation in the natural environment. They capture actual antecedent-behavior-consequence sequences but cannot establish functional relations (correlation ≠ causation).
ABC Narrative Recording:
Observer writes a running narrative of events before, during, and after each instance of the target behavior. Rich qualitative data but difficult to quantify and subject to observer bias.
Structured ABC Data Collection:
Pre-formatted data sheets with columns for time, setting, antecedent, behavior, consequence, and perceived function. Allows quantification of conditional probabilities — how often does behavior X follow antecedent Y and precede consequence Z?
Scatterplot Analysis (Touchette, MacDonald, & Langer, 1985):
Grid mapping behavior occurrence across time intervals and days. Reveals temporal patterns — does behavior cluster during transitions, after lunch, on Mondays? Identifies setting events and slow triggers.
Conditional Probability Analysis:
Calculate: P(behavior | antecedent) vs P(behavior | no antecedent). A high conditional probability for a specific antecedent suggests (but does not prove) a functional relation. Also calculate: P(consequence | behavior) to evaluate which consequences reliably follow behavior.
When indirect and descriptive data yield ambiguous or conflicting hypotheses, experimental functional analysis (see functional-analysis skill) is the gold standard. The FBA practitioner must decide whether available data are sufficient or whether FA is needed.
Triangulation across methods strengthens confidence:
Weight descriptive data over indirect data when they conflict. Weight experimental data over both.
Use the four-term contingency format:
When [antecedent/setting event], the individual [operationally defined behavior], which results in [consequence], and is maintained by [function: specific reinforcement contingency].
Examples:
When presented with non-preferred academic tasks (math worksheets) during independent work time, Marcus engages in head-hitting (forceful contact of closed fist to temporal region of head, 3+ times per minute), which results in task removal by the teacher, maintained by negative reinforcement (escape from demands).
When attention is directed away from Amara toward a peer during free play, Amara engages in screaming (vocalizations above conversational volume lasting 3+ seconds), which results in adult verbal reprimand or redirection, maintained by positive reinforcement (adult attention).
| Function | Reinforcement Type | Antecedent Pattern | Consequence Pattern |
|---|---|---|---|
| Attention | Positive (+SR) | Low attention, attention diverted | Social interaction delivered |
| Escape/Avoidance | Negative (−SR) | Demand, non-preferred activity | Task removal/reduction |
| Tangible/Activity | Positive (+SR) | Restricted access, item/activity removed | Item/activity delivered |
| Automatic (sensory) | Positive or Negative | Variable; may not correlate with social antecedents | Sensory stimulation produced or aversive stimulation attenuated |
FBA alone is sufficient when:
FA is needed when: