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When should a functional analysis be done and who should do it?

This month’s ASAT feature comes to us from Robert LaRue, PhD, BCBA-D. To learn more about ASAT, please visit their website at www.asatonline.org. You can also sign up for ASAT’s free newsletter, Science in Autism Treatment, and like them on Facebook!

I am the parent of a student with autism who has developed some challenging behavior at school and the team has suggested a more formal assessment. What is meant by “functional analysis?” When should this be done and who should do it?

Answered by Robert LaRue, PhD, BCBA-D
Douglass Developmental Disabilities Center and Rutgers Center for Adult Autism Services

Prior to a discussion about functional analysis, it is important to make the distinction between functional analysis and functional assessment. Functional assessment represents a variety of techniques and strategies used to gather information about the cause (or “function”) of challenging behavior. This information is used to maximize the effectiveness and efficiency of behavioral support. There are three broad categories of functional assessment. One category involves talking to caregivers (e.g., parents, teachers) about why problem behavior occurs (i.e., interviews and rating scales). The second type is referred to as descriptive assessment, which involves observing behavior and collecting data regarding the events that precede problem behavior (antecedents) and the events that follow problem behavior (consequences). The third type of functional assessment is functional analysis, which is a more thorough assessment procedure described in more detail below.

What is a Functional Analysis?

A functional analysis (FA) is a specific type of functional assessment that involves the direct manipulation of antecedents and/or consequences to identify why problem behavior occurs (Iwata et al., 1982/1994). In other words, a practitioner conducting an FA directly tests the hypothesis in an experimental manner, rather than waiting for the behavior to occur naturally. For example, if a practitioner wanted to see if problem behavior was maintained by attention from others, they might withhold attention for a brief period of time (e.g., acting distracted) and then provide it if and when problem behavior occurs. As with other forms of functional assessment, the purpose of an FA is to identify why problem behavior occurs. What distinguishes FA from other forms of functional assessment is that FAs involve making deliberate, short-term, and systematic changes to the environment to evaluate the effects of different conditions on the target behavior(s).

In an FA, a practitioner arranges “conditions” that are common in the natural environment (e.g., a teacher presenting non-preferred work tasks, a distracted teacher or parent not attending to a child). While there are many ways to individualize FA conditions, there are four or five conditions that are typically run as part of the assessment.

  • Social Attention: The attention condition is a test to determine if problem behavior occurs to access social attention from others. In this condition, attention is typically withheld (e.g., a therapist acts distracted) and is provided following target behavior for a brief period of time (e.g., 20-30 seconds). This might take the form of a reprimand (e.g., “Stop doing that!”) or soothing comments (e.g., “It’s going to be ok.”). If the individual engages in high rates of inappropriate behavior in this condition as compared to the control condition, it indicates that social attention functions as reinforcement for maladaptive behavior.
  • Tangible: The tangible condition is another test to determine if problem behavior is maintained by access to preferred items or activities. In this condition, access to preferred items is typically withheld (e.g., a toy is removed) and is provided following target behavior. If the individual engages in high rates of inappropriate behavior in this condition, it indicates that problem behavior occurs to access preferred items.
  • Escape: The escape condition is a test to determine if problem behavior occurs to escape demands. In this condition, a nonpreferred activity is typically presented (e.g., school work) and a break (escape) is provided following target behavior for a brief period of time (e.g., 20-30 seconds). If the individual engages in high rates of inappropriate behavior in this condition, it indicates that escape is a reinforcer for maladaptive behavior.
  • Alone or Ignore: The alone or ignore condition is a test for to determine if problem behavior occurs for nonsocial reasons. In other words, the behavior (e.g., hand flapping, repeating words or phrases) is likely to occur when they are by themselves. In this condition, the individual is usually left alone for some period of time to see if the behavior persists when no one else is present. If the behavior persists while no one else is present, it suggests that they are not engaging in the behavior for social reasons. This is sometimes referred to as “automatic reinforcement”. In cases where the behavior is potentially dangerous, or if the individual cannot be left alone, an ignore condition can be implemented where the therapist remains in the room, but does not interact.
  • Control: The control (or toy play) condition serves as the comparison for all of the other conditions. In this condition, the individual has free access to social attention, preferred items/activities, and no demands are present. As such, there is usually very little motivation to engage in problem behavior.

When conducting a traditional FA, each of these conditions are usually conducted at least three to five times, with each session lasting 5 to 15 minutes. Sessions are typically alternated until a clear pattern emerges.

FAs represent the most sophisticated and empirically-supported functional assessment procedures. There are hundreds of studies validating the use of FAs for identifying the function of problem behavior (for a review, see Beavers et al., 2013). In addition, interventions that are based on the results of FAs have consistently been shown to be more effective than those that are not (e.g., Carr & Durand, 1985). In recent years, FA procedures have evolved to become more manageable in educational settings, with modifications that provide results in less time and fewer instances of challenging behavior (e.g., Bloom et al., 2011, Hanley et al., 2014; LaRue et al, 2010; Northup et al., 1991; Smith & Churchill, 2002; Thomasson-Sassi, et al., 2011).

When Should an FA be Conducted?

From a clinical standpoint, functional assessments should be conducted when the student‘s behavior interferes with their own learning or the learning of others, presents a danger to self or others, or the behavior results in suspension or interim placement in an alternative setting approaching 10 total days. FA is a specific procedure for conducting these functional assessments. There are no specific guidelines for when practitioners should use functional analyses rather than other types of assessment. Typically, the use of FA procedures is determined by the skill level of the practitioner, the resources available to the practitioner, and the setting itself.

Who Should Conduct an FA?

Conducting FAs does require a high level of expertise to be done effectively. FAs should be conducted by individuals with experience using the procedures (or while supervised by someone with experience). Many (though not all) people who have board certification in behavior analysis (BCBA) have experience conducting FAs. Consumers should ask practitioners about their level of experience and comfort prior to starting these analyses.


Functional assessments are an essential tool for identifying why problem behavior occurs. Functional analysis is a specific type of functional assessment that is incredibly effective for this purpose. In fact, hundreds of studies have shown FAs to be effective for identifying why problem behavior occurs. In recent decades, user-friendly ways to conduct FAs have emerged, which has made their use more common in educational settings. Most BCBAs should have training to implement FAs safely and efficiently. The use of these procedures can lead to effective, function-based treatments that improve outcomes for children and adults who have behavioral difficulties.


Beavers, G. A., Iwata, B. A., & Lerman, D. C. (2013). Thirty years of research on the functional analysis of problem behavior. Journal of Applied Behavior Analysis, 46(1), 1-21.

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.

Carr, E. G., & Durand V. M. (1985). Reducing behavior problems through functional communication training. Journal of Applied Behavior Analysis, 18, 111-126.

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.

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(2), 197-209.

LaRue, R. H., Lenard, K., Weiss, M. J., Bamond, M., Palmieri, M., & Kelley, M. E. (2010). Comparison of traditional and trial-based methodologies for conducting functional analyses. Research in Developmental Disabilities, 31, 480-487.

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(3), 509-22.

Smith, R. G., & Churchill, R. M. (2002). Identification of environmental determinants of behavior disorders through functional analysis of precursor behaviors. Journal of Applied Behavior Analysis35(2), 125-136.

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(1), 51-67.

Citation for this article:

LaRue, R. (2021). Clinical Corner: When should a functional analysis be done and who should do it? Science in Autism Treatment, 18(12).

About the Author

Robert H. LaRue, Ph.D., BCBA-D is a Clinical Professor at the Graduate School of Applied and Professional Psychology (GSAPP) at Rutgers University. He earned a dual doctorate in biological and school psychology from Louisiana State University in 2002. He completed his predoctoral internship with the Kennedy Krieger Institute at Johns Hopkins University and a postdoctoral fellowship with the Marcus Institute (now the Marcus Autism Center) at Emory University. He currently serves as the Director of Behavioral Services at the Douglass Developmental Disabilities Center (DDDC) and the Rutgers Center for Adult Autism Services (RCAAS), where provides consultative support for students and staff providing intensive behavioral services to students and adults within the Centers. His research interests include the assessment and treatment of maladaptive behavior, improving transitional outcomes for adolescents and adults with ASD, the use of behavioral economics in intervention, and the evaluation of psychotropic medications used with at-risk populations. He has authored articles in peer-reviewed journals, written several book chapters, and presented at national and international conferences.