rbt B.3 Functional Assessment

By RBThub February 23, 2026

If a detective walks into a crime scene, they don't just guess who did it. They look for clues, interview witnesses, and maybe even run an experiment.

In ABA, problem behavior is the "crime." We don't guess why the client is screaming; we investigate. This investigation is called a Functional Behavior Assessment (FBA). It is the only way to find the true function of behavior.

Executive Summary

This video demystifies the FBA (Functional Behavior Assessment). Think of "FBA" as an umbrella term that includes three types of investigation: Indirect (asking), Direct (watching), and Functional Analysis (testing). We learn that you cannot rely on interviews alone; you must see the behavior with your own eyes to treat it effectively.

⏱️ Video Timeline

00:00
The Umbrella Concept
FBA is not just one test. It is a process involving Indirect Assessment, Direct Assessment, and Functional Analysis.
02:20
The Pyramid of Validity
Indirect is easy but inaccurate. Direct (ABC) is better. Functional Analysis (FA) is the "Gold Standard" but hard to do.
05:40
ABC Data (Direct)
The RBT's main job: Recording the Antecedent, Behavior, and Consequence in real-time.
07:30
Functional Analysis (FA)
An experiment where the BCBA triggers the behavior on purpose to prove why it is happening.

🔑 Key Insights

Indirect Assessment: Interviews, Surveys, Checklists. (Asking people).
Direct Assessment: ABC Data, Scatterplots. (Watching the client).
Functional Analysis: Systematically manipulating the environment. (Testing the theory).
The Goal: To find the Function (SEAT: Sensory, Escape, Attention, Tangible).

❓ Frequently Asked Questions

Q: Can I just ask the mom why he is screaming?
A: You can start there (Indirect), but it is not enough. Parents often guess wrong. You must confirm with Direct Observation.
Q: What is the RBT's role in an FA?
A: RBTs usually assist. The BCBA leads the Functional Analysis because it involves intentionally triggering problem behavior, which can be risky.

1. The FBA Hierarchy (The Pyramid)

Think of validity (accuracy) vs. difficulty. As you go up the pyramid, the data gets better, but the work gets harder.
1. Indirect Assessment (Interviews, Surveys) 2. Direct Assessment (ABC Data, Scatterplot) 3. Functional Analysis (Experimental) Easiest Most Accurate

2. ABC Data (The Bread & Butter)

Definition: Recording the Antecedent (what happened before), Behavior (what they did), and Consequence (what happened after).
Antecedent Behavior Consequence
Clinical Example

A: Teacher says "Time for math."
B: Student flips desk.
C: Teacher sends student to the hallway (Escape).
The function is likely Escape from math.

📝 Knowledge Check

Are you a behavior detective?

Q1: Which assessment method involves manipulating variables to test a hypothesis (e.g., intentionally ignoring the child to see if they scream)?

Answer: Functional Analysis (FA).
It is the only "experimental" method. It proves the function.

Q2: You interview the parents and give them a checklist about the child's behavior. What type of assessment is this?

Answer: Indirect Assessment.
You are "asking," not "watching." It is useful but less accurate.
▶

Assessment Quiz

Mock Exam

Test your knowledge on ABC data and Functional Analysis.

Start Practice Test

Comments