Scanlan Center for School Mental Health
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Assessing Externalizing Behaviors in School-Aged Children: Implications for School and Community Providers

Externalizing behavior problems encompass a wide range of acting out behavior difficulties with the (external) environment, including behaviors such as aggression, bullying, conduct problems, callousness, inattention, hyperactivity, oppositionality, rule breaking, defiance, substance use, and disruptive behavior.

Externalizing problems are prevalent in school-aged children and are costly and burdensome to individuals, families, schools, and society. Externalizing problems are disruptive to classrooms and make it challenging for educators to focus on teaching and for the child and classroom to learn. Moreover, early externalizing problems can predict later, more severe problems like violence if left untreated, so accurate assessment of externalizing problems is crucial to ensure children and adolescents receive the services they need.

The goal of this practice brief is to help clinicians and school psychologists conduct accurate assessments of externalizing behavior in school-aged children to support effective intervention and prevention.

Identification/Assessment Strategies

Conduct a Multi-Stage Approach to Assessment

Effective assessment of externalizing behaviors uses a multi-stage approach including screening, using multiple assessment methods, interpreting results, designing the treatment plan, and evaluating treatment progress (Volpe & Chafouleas, 2011; Youngstrom & Van Meter, 2016).

Consider the Goals of the Assessment

When selecting assessment tools to use, it is important to consider the goals of the assessment process. Various goals of assessment include (a) screening, (b) diagnosis, (c) monitoring progress, (d) and characterizing the full range of strengths and difficulties. Different assessments should be selected depending on the goal(s).

Another consideration is whether to assess behavior problems at a more general, broad-band level (e.g., externalizing problems), or in more specific, narrow-band ways—e.g., callous-unemotional behaviors, inattention/impulsivity/hyperactivity, oppositionality, aggression, conduct problems, or substance use. Assessments that focus on broad-band problems tend to provide limited depth in any specific concern (Collett et al., 2003).

If time allows, it can be helpful to include both the assessment of general, broad-band problems as well as more focused assessment of narrow-band problem dimensions in the areas of greatest potential concern (Achenbach et al., 2016).

Screening devices tend to be brief, broad-band, and aim to identify children who are at risk of showing clinically significant problems in their current or future behavior. Schools often implement school-wide screening. Because screening devices aim to identify children who are at risk, screening devices focus on differentiating the top half of the distribution (i.e., the 50th percentile of misbehavior and above) as briefly (i.e., with as few items) as possible.

Another purpose of assessment may be to monitor a child’s progress, such as their response to treatment. Instruments designed to monitor progress tend to be brief, so they can be completed regularly (e.g., daily or weekly). A consideration for such measures is whether it is sensitive to change to detect improvement in a child’s behavior over a short timeframe.

A fourth purpose of assessment may be to characterize the full range of a child’s strengths and difficulties. Here, the goal is to determine where in the distribution (e.g., what percentile) the child is relative to their peers on dimension(s) of interest (e.g., aggression). Such instruments are longer because they aim to differentiate children across the full distribution (i.e., 1st to 99th percentile), which requires items that differ in severity and requires more items.

Other Considerations When Selecting Assessment Tools

Other important considerations when selecting assessments include psychometrics: reliability and validity. That is, scores from a given measure should be precise and accurate for the intended construct (i.e., externalizing problems), population, and purpose. The psychometric properties of measures are reviewed by Sattler (2022) and the Buros Mental Measurements Yearbook.

It is important to consider whether the measure’s content and items are developmentally appropriate for the child’s age and developmental level (Wakschlag & Danis, 2004). In addition, it is important to consider whether the measures’ scores and norms are appropriate for special populations, including those with intellectual disabilities, those in the child welfare system (Keil & Price, 2006), and those who may not be proficient in English (Paalman et al., 2013). If the instruments used do not have established validity or norms with respect to the particular population of interest (e.g., 13-year-olds), it is important to note potential interpretive concerns in any reports.

Use Multiple Methods and Perspectives at Multiple Time Points

It is best to conduct the assessment with at least two assessment methods and at least two perspectives, at multiple points in time (Lochman et al., 2001). Assessment methods include questionnaires, interviews, observations, behavior tracking, and school records (e.g., Walker et al., 1991).

It is preferable for the perspectives represented to span the home and school contexts. Perspectives could include, for instance, parents, teachers, other caregivers, the child, siblings, and peers. Easily observable misbehavior may be best reported by informants, whereas more hidden or covert misbehavior may require self-report. To ensure validity, the assessments should be administered and interpreted by licensed professionals who are trained to use them.


Questionnaires can be a quick, easy way to collect information from multiple informants. However, questionnaires have limitations, including (a) they require respondents to be able to read proficiently in the language, (b) they involve informant bias, (c) they often have subjective response formats (e.g., “sometimes”, “often”) that lead to bias and imprecision, and (d) they do not provide systematic opportunities for respondents to ask clarifying questions or for examiners to ask follow-up questions, making it more likely that a respondent will misinterpret a question.

One of the most widely used assessments of externalizing problems is the Achenbach System of Empirically Based Assessment (ASEBA). The ASEBA includes assessment of broad-band problems as well as more narrow-band problems, and it includes varying items for different informants and ages to maintain developmental and contextual relevance. For instance, parents provide reports on the Child Behavior Checklist, which has different versions based on the child’s age.

Teachers provide reports on the Teacher’s Report Form, which also has different versions based on the child’s age. The ASEBA also includes an optional Multicultural Supplement with multicultural norms. Moreover, the ASEBA includes a brief form, the Brief Problem Monitor that is more sensitive to change for the purposes of monitoring progress.

The Peer-report Measure of Internalizing and Externalizing Behavior uses peer nomination to identify externalizing problems. Another widely used questionnaire of externalizing problems is the Strengths and Difficulties Questionnaire*. It assesses functional impairment, has different forms for various ages and informants, and has translated versions in many languages. A questionnaire that is well-suited to study the full range of strengths and weaknesses is the Extended Strengths and Weaknesses of Normal Behavior*.

In addition to broad-band questionnaires, there are also questionnaires designed to assess more narrow-band problems, including for callous-unemotional behaviors (Inventory of Callous-Unemotional Traits*), inattention/impulsivity/hyperactivity (Conners 4), oppositionality (Disruptive Behavior Disorder Rating Scale*), aggression (Children’s Aggression Scale), conduct problems (Conduct Disorder Rating Scale), or substance use (Problem-Oriented Screening Instrument for Teenagers*). The Conners 4 is also available in Spanish and French.


Interviews are another common form of assessment. Interviews do not require respondents to be able to read, and they allow examiners to ask follow-up questions. However, interviews take more time to conduct than questionnaires and can be subject to confirmatory bias on the part of the interviewer. For instance, interviewers tend to assess only the behavior problems that fit their hypotheses of the child’s difficulties (Sharp et al., 2013). To prevent confirmatory bias, it is important to use structured or semi-structured interview approaches and to supplement the approach with assessments that span a wider array of potential difficulties than the clinician’s hypotheses might suggest.

Some interviews assess broad-band problems, whereas others focus on more narrow-band problems. General interviews include the Schedule for Affective Disorder and Schizophrenia for School-Age Children*, Child and Adolescent Psychiatric Assessment (CAPA)*, and Development and Well-Being Assessment* (DAWBA). CAPA has a child interview and a parent interview. The DAWBA has translations in many languages. Interviews that are focused on externalizing behavior include the Disruptive Behavior Disorders Parent Interview*, Kiddie Disruptive Behavior Disorders Schedule, and Clinical Parent Interview for Externalizing Disorders in Children and Adolescents. An interview focused on callous-unemotional behavior is the Clinical Assessment of Prosocial Emotions*.


Observational assessment is a valuable assessment process for externalizing behaviors. Observations are less influenced by informant bias. However, observations can be time consuming to conduct. Moreover, during a brief observation period, it may be unclear how representative a child’s behavior is of their behavior in other situations or contexts, especially if the child acts differently because they are being observed (i.e., reactivity). In addition, if the target behavior is infrequent or covert, it can be more difficult to observe.

A widely used approach to observational assessment is functional behavior assessment (FBA). FBA involves observing patterned sequences of antecedents and consequences of the target problem behavior to generate and test potential hypotheses regarding the function(s) of the behavior, which can be useful in intervention (Broussard & Northup, 1995; Gresham, 2015).

The same behavior can occur for different reasons, and it is important to know why the child engaged in the problem behavior, because each function might be targeted differently in intervention. Common hypotheses regarding the functions of problem behavior include approach- (e.g., access to attention or access to tangibles, such as toys or preferred activities) and avoidance-related functions (e.g., escape from undesirable situations).

When conducting observational assessments, it is helpful to observe the child in different situations (e.g., lunch time, recess, math work), times of day (e.g., morning, afternoon, evening), and contexts (e.g., home, school). Rating specific behaviors close to when they are exhibited is helpful for monitoring progress (Daniels et al., 2021).

Schools may also have FBA processes and tools developed by their district, intermediate service agencies, or state departments of education that they are required to use as part of processes like multi-tiered systems of support (MTSS) and special education identification. In addition to FBA, several observational assessments have been developed for externalizing behavior, including the ADHD School Observation Code, ADHD Behavior Coding System, Disruptive Behavior Diagnostic Observation Schedule, Direct Observation Form, Adjustment Scales for Children and Adolescents, Overt Aggression Scale, Revised Edition of the School Observation Coding System, and Classroom Observation Code. There are also playground-based observational systems (Leff & Lakin, 2005).

Behavior Tracking 

Behavior tracking is a form of observational assessment that aims to assess children prospectively in a less time-consuming way. For instance, it may involve the parent or teacher making a tally for each instance of various behaviors, including compliance, noncompliance, and aggression. Behavior tracking is sensitive to change and is therefore particularly useful for progress monitoring. For instance, behavior tracking may allow practitioners to evaluate whether the frequency of the target problem behaviors change on a day-to-day or week-to-week basis.

Handling Informant Discrepancies

Informants (e.g., parent, teacher) often disagree about the extent to which a given child shows behavior problems. Informant discrepancies likely occur for many reasons, including (a) the child may behave differently in different contexts and/or with different people, (b) informants may have differing knowledge and perspectives of what is developmentally typical versus atypical; for instance, teachers may generally have a wider range of comparisons than parents and may thus be uniquely positioned to rate the child, (c) there may be cultural differences in what is considered developmentally appropriate behavior, (d) informants have biases to respond in particular ways, and (e) measurement error. To handle informant discrepancies when there is not a clear primary informant who is best positioned to rate the child most accurately, one can count a symptom as present if it is endorsed by any of the informants (Hinshaw & Nigg, 1999).

What to Assess

It is important to assess many facets of the problem behavior, including its frequency, intensity/severity, onset, and duration; that is, how long it has been occurring, how frequently it occurs, and how intense or severe the behavior is when it occurs. It is also important to consider potential function(s) of the misbehavior (Reitman et al., 1998). Functional impairment should also be considered. For instance, it is important to consider whether the behavior impedes the child’s ability to perform well in school, to hold a job, or to develop meaningful relationships with peers, teachers, and family members. In addition, it is important to consider cultural and contextual factors, including the family and social context (Knapp et al., 2012).

It is also important to consider co-occurring issues and conditions. Many cognitive, academic, emotional, behavioral, and medical difficulties commonly co-occur with externalizing problems and are important to assess. Commonly co-occurring issues include internalizing problems (e.g. mood and anxiety-related problems; Achenbach et al., 2016; Cunningham et al., 2013), intellectual disabilities, learning disorders, academic difficulties, neurodevelopmental conditions such as autism, and problems related to sleep, feeding (e.g., picky eating), and voiding (e.g., enuresis, encopresis; McKinney & Morse, 2012) .

Data Privacy and Sharing

Federal laws protect the privacy of protected health information (HIPAA) and of educational records (FERPA). It can be helpful for clinicians, schools, and families to work together to address a child’s needs. To achieve this, it is important to obtain informed consent and two-way releases of information to ensure that the clinician can share information with the school, and that the school can share information with the clinician.

For instance, a parent and teacher might rate the child’s behavior for a clinician conducting an assessment. The clinician then might share their assessment results and a suggested treatment plan with the family and might work with the teacher and family to help them enact the treatment plan. The school may then share the child’s treatment progress with the family and clinician.

Putting It Altogether

With the assessment information collected, the clinician can develop a case formulation that considers predisposing factors, precipitating factors, perpetuating factors, and protective factors for the given child’s misbehavior. Such a case formulation is helpful when developing a treatment plan.

Intervention often aims to address a child’s perpetuating/maintaining factors (e.g., low frustration tolerance; ineffectual caregiver responses) and minimize how frequently the triggering situations occur, while building on the child’s strengths and considering predisposing factors (e.g., family history, temperament).

To maximize the usefulness of assessment results for schools, it is important to write a concise and clear report and be timely and attentive to requests for data sharing. In sum, externalizing behavior problems in school-aged children are prevalent, burdensome, and important to assess and address.

Key Implications for Practice

  • Conduct a multi-stage approach that includes screening, multi-method assessment, interpreting results, designing the treatment plan, and evaluating treatment progress.
  • Select measures based on their psychometrics, their intended depth and breadth, and the goals of the assessment: screening, diagnosis, monitoring progress, or patterns of strengths and weaknesses.
  • Consider cultural and contextual factors and co-occurring issues.
  • Incorporate multiple perspectives (e.g., parents and teachers) and methods, including observational assessment, across multiple time points.
  • Consider frequency, intensity, duration, functions, and impairment of problem behaviors.
  • Develop a case formulation based on predisposing, precipitating, perpetuating, and protective factors for the child’s problem behaviors.
  • Ensure information sharing forms are completed and reports are shared with families and schools, so that schools can use the information in their planning and delivery of services.

Related Resources

* indicates an assessment instrument that is freely and publicly available

Achenbach, T. M., Ivanova, M. Y., Rescorla, L. A., Turner, L. V., & Althoff, R. R. (2016). Internalizing/externalizing problems: Review and recommendations for clinical and research applications. Journal of the American Academy of Child & Adolescent Psychiatry, 55(8), 647–656.

Broussard, C. D., & Northup, J. (1995). An approach to functional assessment and analysis of disruptive behavior in regular education classrooms. School Psychology Quarterly, 10, 151–164.

Collett, B. R., Ohan, J. L., & Myers, K. M. (2003). Ten-year review of rating scales. VI: Scales assessing externalizing behaviors. Journal of the American Academy of Child & Adolescent Psychiatry, 42(10), 1143–1170.

Cunningham, N. R., Wolff, J. C., & Jarrett, M. A. (2013). Assessment of disruptive behavior disorders in anxiety. In D. McKay & E. A. Storch (Eds.), Handbook of Assessing Variants and Complications in Anxiety Disorders (pp. 231–241). Springer New York.

Daniels, B., Briesch, A. M., Volpe, R. J., & Owens, J. S. (2021). Content validation of direct behavior rating multi-item scales for assessing problem behaviors. Journal of Emotional and Behavioral Disorders, 29(2), 71–82.

Gresham, F. M. (2015). Disruptive behavior disorders: Evidence-based practice for assessment and intervention. Guilford Publications.

Hinshaw, S. P., & Nigg, J. T. (1999). Behavior rating scales in the assessment of disruptive behavior problems in childhood. In D. Shaffer, C. P. Lucas, & J. E. Richters (Eds.), Diagnostic assessment in child and adolescent psychopathology. (pp. 91–126). The Guilford Press.

Keil, V., & Price, J. M. (2006). Externalizing behavior disorders in child welfare settings: Definition, prevalence, and implications for assessment and treatment. Children and Youth Services Review, 28(7), 761–779.

Knapp, P., Chait, A., Pappadopulos, E., Crystal, S., Jensen, P. S., & on behalf of the T-MAY Steering Group. (2012). Treatment of maladaptive aggression in youth: CERT guidelines I. Engagement, assessment, and management. Pediatrics, 129(6), e1562–e1576.

Leff, S. S., & Lakin, R. (2005). Playground-based observational systems: A review and implications for practitioners and researchers. School Psychology Review, 34(4), 475–489.

Lochman, J. E., Dane, H. E., Magee, T. N., Ellis, M., Pardini, D. A., & Clanton, N. R. (2001). Disruptive behavior disorders: Assessment and intervention. In H. B. Vance & A. J. Pumariega (Eds.), Clinical assessment of child and adolescent behavior. (pp. 231–262). John Wiley & Sons, Inc.

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Volpe, R. J., & Chafouleas, S. M. (2011). Assessment of externalizing behavioral deficits. In M. A. Bray & T. J. Kehle (Eds.), The Oxford handbook of school psychology (pp. 284–311).

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Walker, H., Block-Pedego, A., Todis, B., & Severson, H. (1991). School archival records search. Longmont, CO: Sopris West.

Youngstrom, E. A., & Van Meter, A. (2016). Empirically supported assessment of children and adolescents. Clinical Psychology: Science and Practice, 23(4), 327–347.