Functional Behavioral Assessments: What? Why? How? Who?

by Stephen Starin, Ph.D. – The recent amendments to IDEA are final. School districts are now required to conduct functional behavioral analyses of problem behaviors, under certain circumstances.


Unfortunately, IDEA does not provide specific guidelines regarding the conduct of a functional behavioral assessment. Each school district is left to its own devices when interpreting the guidelines and may opt for lower quality standards.

Below are my comments on conducting a functional behavioral assessment (FBA). These comments are based upon my formal training as a behavior analyst and over 20 years experience working with children, adolescents, and adults with serious problem behaviors. I’ve tried to avoid technical jargon for ease of discussion.

What is a “Functional Behavioral Assessment”?

The term “Functional Behavioral Assessment” comes from what is called a “Functional Assessment” or “Functional Analysis” in the field of applied behavior analysis. This is the process of determining the cause (or “function”) of behavior before developing an intervention. The intervention must be based on the hypothesized cause (function) of behavior.

Why Do Functional Behavioral Assessments?

Failure to base the intervention on the specific cause (function) very often results in ineffective and unnecessarily restrictive procedures.

For example, consider the case of a young child who has learned that screaming is an effective way of avoiding or escaping unpleasant tasks. Using timeout in this situation would provide the child with exactly what he wants (avoiding the task) and is likely to make the problem worse, not better. Without an adequate functional behavioral assessment, we would not know the true function of the young child’s screaming and therefore may select an inappropriate intervention.

How Do You Determine the Cause or Function of Behavior?

There are three ways of getting at the function (cause) of the behavior:

(a) interviews and rating scales,
(b) direct and systematic observation of the person’s behavior, and
(c) manipulating different environmental events to see how behavior changes.

The first two are generally referred to as functional assessments whereas the third is generally referred to as a functional analysis.

Several different interviews and rating scales have been developed to try to get at the function (cause) of behavior. However, reliability is usually poor and these should be used only as a starting point for systematic and direct observation of the person’s behavior. Relying exclusively on interviews and rating scales should neverbe considered a functional assessment. Besides having poor reliability, it would never hold up in court with an expert witness.

A more reliable method involves directly observing the person’s behavior in his or her natural environment and analyzing the behavior’s antecedents (environmental events that immediately precede the problem behavior) and consequences (environmental events that immediately follow the problem behavior).

Types of Problem Behavior

Problem behavior typically falls into one or more of three general categories:

(a) behavior that produces attention and other desired events (e.g., access to toys, desired activities),
(b) behavior that allows the person to avoid or escape demands or other undesired events/activities, and
(c) behavior that occurs because of its sensory consequences (relieves pain, feels good, etc.).

The antecedents and consequences are analyzed to see which function(s) the behavior fulfills. Problem behavior can also serve more than one function, further complicating the matter. The interview, combined with direct observation of the behavior is what most people use in determining the function of the behavior. This is fine when the data collected on the antecedents and consequences is clear. Most of the time this is sufficient in determining the behavior’s function(s).

Systematic Manipulation of Environment

In some cases, however, direct observation does not give a clear picture of the behavior’s functions and systematically manipulating various environmental events becomes necessary. The most common way of systematically manipulating the environment is to put the person in several different situations and carefully observe how the behavior changes.

For example, to determine the function of screaming, we could arrange for attention to be given to the child each time she screams and measure how frequently screaming occurs. We could also make demands on the child, terminating them each time she screams and measure how frequently it occurs. In addition, we could leave the child alone and measure how often screaming occurs. If screaming is more frequent when attention is given, we hypothesize that it occurs to get attention. If screaming is more frequent when demands are made, we can assume that screaming has served to let the person escape or avoid demands. Finally, if screaming is more frequent when left alone, we can assume that it is occurring because of its sensory consequences. This third method should be reserved only for situations in which the functions of behavior are not clear through systematic and direct observation.

What About Qualifications and Training?

An important question is “Who should be involved in the functional behavioral assessment?” The interview is important in gathering preliminary information that will guide later direct observation. As such, it is important to talk to the people who know the child the best: parents, teachers and significant others.

Direct observation should be carried out only by a person who has been thoroughly trained on collecting and analyzing this type of information. Directly manipulating environment events should be conducted only by a well-trained behavior analyst or someone else with a high degree of training and experience conducting these manipulations for they can pose danger to the person if not done correctly.

As can be seen, a functional behavioral assessment is more than a group of people sitting around a table trying to determine the cause. Although it is important to gather information from significant people in the person’s life, it is not enough.

Someone knowledgeable about behavior must be in the classroom and/or family home directly observing and measuring the behavior. Although this takes time, it is usually time well spent because the intervention is more likely to be effective than one developed without careful consideration of the behavior’s function(s).

Don’t Waste Valuable Time!

Time is precious. Time should not be wasted on interventions (behavioral or otherwise) when there is no evidence that this particular intervention is likely to work, for this particular child, in this particular situation.

Wrightslaw – Functional Behavioral Assessments: What? Why? How? Who? by Stephen Starin, Ph.D..

Jimmy Kilpatrick, a national recognized professional special education advocate since 1994.

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