Use when designing, conducting, or interpreting experimental functional analyses — covers standard FA, brief FA, trial-based FA, IISCA, latency-based FA, precursor FA, and safety protocols.
Functional analysis is the experimental demonstration of a functional relation between environmental events and behavior. Unlike descriptive or indirect assessment, FA involves systematic manipulation of antecedents and consequences to observe their effect on behavior under controlled conditions. It is the only assessment method that establishes causation.
Standard Functional Analysis (Iwata et al., 1982/1994)
The standard multielement (alternating treatments) FA includes four test conditions and one control condition. Sessions typically last 10-15 minutes, with 3-5 sessions per condition minimum.
Attention Condition
Purpose: Test whether behavior is maintained by social-positive reinforcement (attention)
Antecedent arrangement: Therapist is present but attention diverted (e.g., reading a magazine). Moderately preferred items available. No demands.
Contingent on appropriate behavior: Nothing (attention withheld).
Escape/Demand Condition
Purpose: Test whether behavior is maintained by social-negative reinforcement (escape from demands)
Antecedent arrangement: Therapist presents academic or instructional demands using a three-step guided compliance procedure (verbal → model → physical prompt). Continuous task presentation.
Contingent on target behavior: Demand removed for 20-30 seconds (therapist turns away, materials removed).
Contingent on appropriate behavior: Brief praise delivered on a lean schedule; demands continue.
Tangible Condition
Purpose: Test whether behavior is maintained by access to preferred items/activities
Antecedent arrangement: Preferred item present but restricted (removed after brief pre-session access). Therapist present but not attending.
Contingent on target behavior: Item/activity delivered for 20-30 seconds.
Contingent on appropriate behavior: Item remains restricted.
Alone/Ignore Condition
Purpose: Test whether behavior is maintained by automatic reinforcement
Antecedent arrangement: Individual is alone in a therapy room (or therapist present but providing no interaction). No demands. No or minimal materials.
Contingent on target behavior: No programmed consequences — behavior produces only its naturally occurring sensory consequence.
Key distinction: "Alone" = no one present (monitored remotely). "Ignore" = therapist present but provides zero social interaction. Use "ignore" when safety requires presence.
Control/Play Condition
Purpose: Control for attention, demands, and tangible deprivation
Antecedent arrangement: Continuous attention (therapist engages in play/conversation), no demands, preferred items freely available.
Contingent on target behavior: Nothing (brief planned ignoring — redirect if dangerous).
Expectation: Low or zero rates of behavior. If behavior remains high in control, consider automatic reinforcement or inadequate control condition.
Interpreting Standard FA Results
Clear differentiation: Behavior elevated in one test condition relative to control → function identified.
Attention-maintained: Elevated in attention condition only.
Escape-maintained: Elevated in demand condition only.
Tangible-maintained: Elevated in tangible condition only.
Automatically maintained: Elevated across all conditions (including alone) or elevated in alone with low rates in control.
Multiply maintained: Elevated in two or more test conditions — design interventions addressing all maintaining variables.
Undifferentiated: No clear pattern across conditions. Consider: (a) synthesized contingency analysis, (b) modified conditions with idiosyncratic variables, (c) extended sessions, (d) return to descriptive assessment.
Brief Functional Analysis (Northup et al., 1991)
Designed for outpatient/clinic settings where extended assessment is impractical.
Procedure:
Conduct one session per condition (approximately 5-10 minutes each)
Identify the condition with the highest rate
Conduct a contingency reversal: (a) present the hypothesized reinforcer contingent on alternative behavior, (b) then return to test condition
If behavior decreases during reversal and increases upon return → function confirmed
Advantages: Time-efficient (can complete in 60-90 minutes). Useful for clinic-based assessments.
Limitations: Fewer data points increase risk of false positives/negatives. May miss lower-frequency functions. Less useful for automatic reinforcement.
Designed for classroom implementation without removing the student to a clinical setting.
Procedure:
Each "trial" consists of a test segment (~2 minutes) and a control segment (~2 minutes)
Trials embedded in natural routines throughout the school day
Record binary outcome: behavior occurred (yes/no) within each segment
Conduct 5+ trials per condition across multiple days
Compare percentage of trials with behavior occurrence across test vs. control segments
Data Analysis:
Calculate percentage of trials with behavior occurrence per condition. Compare to control. Differentiation follows same logic as standard FA.
Advantages: Ecologically valid, does not require pullout, teachers can implement with training, brief segments reduce exposure to reinforcement of problem behavior.
Limitations: Binary data loss sensitivity to rate differences. Cannot capture within-session patterns.
Interview-Informed Synthesized Contingency Analysis (IISCA; Hanley et al., 2014)
A practical, efficient alternative to the standard multielement FA, particularly useful when behavior is multiply controlled.
Conduct detailed interview with caregivers to identify:
Specific establishing operations (what makes behavior more likely)
Specific reinforcers (what the individual is trying to access or avoid)
The temporal sequence of events surrounding behavior
This is NOT a checklist — it is a conversational, Socratic interview that drills into the specifics of everyday routines.
Step 2: Test Condition (Synthesized)
All relevant establishing operations are presented simultaneously:
Demands + attention removal + tangible restriction + any other identified EOs
Contingent on target behavior: all identified reinforcers delivered simultaneously (demands removed + attention provided + tangible delivered)
Step 3: Control Condition
All reinforcers freely available:
No demands, continuous attention, preferred items available
Contingent on target behavior: nothing (or brief planned ignoring)
Interpreting IISCA Results
Differentiated: Higher rates in test than control → synthesized function confirmed
Use the interview data to decompose the synthesized contingency into its components for intervention planning
Subsequent component analyses can isolate which specific variables are most influential
Advantages: Efficient (2 conditions, not 5). Higher social validity. Captures multiply controlled behavior naturally. Strong evidence base for linking to Practical Functional Communication Training (PFCT).
Limitations: Relies heavily on interview quality. Confirms synthesized function but doesn't parse individual functions without additional component analysis.
Latency-Based FA (Thomason-Sassi et al., 2011)
Measures latency to first response rather than rate. Useful when:
Behavior is high-intensity and even one instance is dangerous (SIB, aggression)
Ethical concerns about allowing multiple instances per session
Standard rate measures would expose individual or others to unacceptable risk
Procedure: Same conditions as standard FA, but sessions terminate after the first instance of behavior. Record latency from session onset to first occurrence. Shorter latencies in a test condition suggest that function.
Precursor Functional Analysis
When target behavior is too dangerous for standard FA, identify a less intense precursor behavior in the response chain and analyze that instead.
Procedure:
Identify the behavioral chain leading to the dangerous behavior
Identify a reliable precursor (e.g., verbal threats before aggression, hand-raising before SIB)
Conduct FA on the precursor
If precursor and target share the same function (validated through at least partial analysis), design intervention for the entire chain
Safety Considerations
Establish session termination criteria BEFORE beginning (e.g., "session ends after 3 instances of SIB" or "if protective equipment is breached")
Have protective equipment available (padded surfaces, helmets, blocking shields)
Staff trained in safe physical management
Medical clearance when SIB is present
Two staff minimum — one implementing, one collecting data and monitoring safety
Discontinue if behavior escalates beyond pre-established safety limits
Document all incidents and safety decisions in the FA record
IRB/Human Rights Committee approval may be required in some settings
Procedural Integrity
Calculate and report procedural integrity (IOA) for:
Correct antecedent arrangement per condition
Correct consequence delivery (within 3-5 seconds of behavior)
Correct timing of session components
Minimum 80% integrity for data to be interpretable; 90%+ preferred
Conduct integrity checks on at least 30% of sessions
Have an independent observer score procedural integrity on a checklist
When NOT to Conduct an FA
FBA data clearly converge on a single function with high confidence
Safety risks exceed what can be managed with available resources and personnel
The individual's history and medical condition make exposure to EOs contraindicated
Institutional or family consent cannot be obtained
The setting lacks trained personnel to implement and monitor conditions safely
The behavior occurs so infrequently that experimental sessions would not capture it
Key References
Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., & Richman, G. S. (1982/1994). Toward a functional analysis of self-injury. Journal of Applied Behavior Analysis, 27, 197–209.
Hanley, G. P., Jin, C. S., Vanselow, N. R., & Hanratty, L. A. (2014). Producing meaningful improvements in problem behavior of children with autism via synthesized analyses and treatments. Journal of Applied Behavior Analysis, 47, 16–36.
Northup, J., Wacker, D., Sasso, G., Steege, M., Cigrand, K., Cook, J., & DeRaad, A. (1991). A brief functional analysis of aggressive and alternative behavior in an outclinic setting. Journal of Applied Behavior Analysis, 24, 509–522.
Bloom, S. E., Iwata, B. A., Fritz, J. N., Roscoe, E. M., & Carreau, A. B. (2011). Classroom application of a trial-based functional analysis. Journal of Applied Behavior Analysis, 44, 19–31.
Thomason-Sassi, J. L., Iwata, B. A., Neidert, P. L., & Roscoe, E. M. (2011). Response latency as an index of response strength during functional analyses of problem behavior. Journal of Applied Behavior Analysis, 44, 51–67.
Hanley, G. P. (2012). Functional assessment of problem behavior: Dispelling myths, overcoming implementation obstacles, and developing new lore. Behavior Analysis in Practice, 5, 54–72.