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Functional Behavioral Assessments

Federal law requires functional behavioral assessment to be part of disciplinary procedures (manifest determinations). These guidelines apply to all students in special education, including those with ASD; however, there are many other times when determining the purpose or function of a behavior is beneficial.

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Federal law requires functional behavioral assessment to be part of disciplinary procedures (manifest determinations). These guidelines apply to all students in special education, including those with ASD; however, there are many other times when determining the purpose or function of a behavior is beneficial.

A functional behavioral assessment, or FBA, is used to better understand the pattern and purpose, or function, of a behavior. Horner and Carr (1997) defined FBA as “a method for identifying the variables that reliably predict and maintain problem behavior” (p. 84). The goal of FBA is to identify events that precede (antecedents) and follow (consequences) a behavior. Careful analysis of antecedents, behavior, and consequences (the ABCs) provides insight into the purpose or function of a behavior. It is important to understand the function of a behavior in order to develop more effective interventions. Indeed, research has demonstrated that the use of FBA increases the effectiveness of interventions (Carr et al., 1999; Ellingson, Miltenberger, Stricker, Galensky, & Garlinghouse, 2000).

According to Gresham, Watson, and Skinner (2001), “FBA is not a single test or observation, but rather a multimethod strategy” (p. 158). A thorough FBA includes interviews with parents, teachers, and the student; classroom observations; and a review of records. At times, understanding the purpose of the behavior also requires altering elements in the environment to see how behavior changes; this is known as functional analysis.

According to Grossman and Aspy (2011), considering patterns of behavior through FBA is useful but has one important limitation: the FBA model focuses exclusively on observable behaviors without consideration of the underlying ASD characteristics. Grossman and Aspy (2011) assert that characteristics of ASD contribute to the observed behaviors and conclude that it is, therefore, important to consider the ASD characteristics. Failure to understand or consider these characteristics when designing behavior interventions presents risks for students, as described by Grossman and Aspy. In addition, others have argued that biological factors such as hunger or anxiety (Carr, 1994) and diagnostic characteristics and genetic conditions (Reese, Richman, Zarcone, & Zarcone, 2003) should also be considered when examining behavior. In the case of the latter, the authors noted, “An evaluation of the interaction between diagnostic characteristics and environmental events may lead to a more individualized functional assessment of challenging behavior displayed by young children with autism” (Reese et al., 2003, p. 88). For example, Reese and colleagues pointed out that gaining access to perseverative activities and escaping demands while engaged in these activities frequently contribute to disruptive behavior. Moreover, the emotional state of persons with ASD may affect motivation behind a target behavior (Joosten & Bundy, 2008; Joosten et al., 2009).

Those who do not understand the characteristics of ASD are likely to perceive individuals with the disorder as being poorly behaved or as “needing more discipline.” It is critical for teachers, parents, and others in helping roles to be able to recognize characteristics of ASD that may underlie challenging behaviors. Importantly, however, not all behavioral difficulties are related to the underlying disorder. Indeed, individuals with ASD may willfully choose to engage in inappropriate behaviors; however, misinterpreting behaviors as willful when they are not carries great risks. A history of being punished for behavior that is related to an underlying disorder may result in low self-esteem, hopelessness, depression, and a lack of opportunity to learn alternative behaviors. When in doubt, it is best to respond to a behavioral difficulty as if it is related to the underlying ASD. For this reason, those who wish to design effective behavior interventions must know the characteristics of the disorder.

Functional behavioral assessment is a useful tool when used by those who understand ASD. Many instruments for functional behavioral assessments have been developed. Included within this section of the TARGET is summary information about the following functional behavioral assessments:

ABC-Iceberg (ABC-I)

  • Functional Assessment Checklist: Teachers and Staff (FACTS)
  • Functional Assessment Interview (FAI)
  • Motivation Assessment Scale (MAS)
  • Questions About Behavioral Function (QABF)
  • Student-Directed Functional Assessment Interview (SDFAI)

The following summary of functional behavioral assessments is not intended to be all-inclusive. Rather, the assessments were selected based on their prevalence within clinical and academic settings as well as their relevance to children with ASD.

Many of the measures described in this section are indirect, in that data gathered is from observers such as parents or teachers, rather than direct assessment, as is conducted when a trained professional systematically gathers data as described in the previous section. In general, compared with indirect approaches, direct methods of FBA are noted to be stronger in terms of validity (McIntosh, Borgmeier, Anderson, Horner, Rodriguez, & Tobin, 2008). However, combining direct and indirect FBA approaches may be the best way to capture information most useful for developing useful behavior interventions (Fee, Shieber, Noble, & Valdovinos, 2016; Watkins & Rapp, 2013). Research described in the following section, and synthesized here, primarily focuses on comparing indirect assessment results to outcomes of direct assessment.

In a review of 10 research studies examining psychometric properties of the FACTS (including research specific to ASD population use), moderate to strong evidence was found in terms of convergent validity with direct observation and functional analysis procedures, strong evidence of treatment utility, and strong evidence of social validity. Inconsistent agreement was found between the FAI and direct assessment, though results were nuanced in that the FAI was more consistent with direct assessment in terms of identifying escape functions, while the QABF was most consistent for identify attention function (Fee et al., 2016).

Some research has also investigated relationships between indirect functional behavioral assessment measures themselves. For example, the QABF and MAS—both of which are unique in that they result in quantitative scores that suggest possible functions of problem behaviors— were more highly correlated with each other than with results from the analogue sessions, and the QABF was more highly correlated with analogue sessions than the MAS (Paclawskyj et al., 2001).



Functional Behavioral Assessment (FBA) is an intervention.


FBA is a process for understanding the purpose of behavior; it assists in developing interventions.


Because FBAs are conducted routinely, they do not require parental consent.


FBAs are a form of assessment that require parental consent.


FBAs are conducted only for manifestation determinations.


While it is true that an FBA is required to conduct a manifestation determination, Sugai and Horner (1999-2000) note that the main purpose of an FBA is to develop a more effective intervention plan and, therefore, is not limited to use in such instances.


“Control,” “bullying,” and “anger management” may sometimes be the function of a behavior.


These labels are inappropriate because they are not behavioral concepts, and they blame the student.