Abstract School psychologists are increasingly adopting a response to intervention (RTI) approach to the assessment and treatment of children. This presentation describes evidence-based assessment of ADHD based on a chapter to appear in the fifth edition of Best Practices in School Psychology (Tobin, Schneider, Reck, & Landau, in press). Specifically, an ADHD assessment strategy is presented that follows guidelines prescribed by Pelham, Fabiano, and Massetti (2005). This presentation also describes assessment in the context of RTI and three-tier model of service delivery for children with ADHD. Introduction Following the now universally embraced movement towards evidence- based treatment (EBT) for children’s behavior disorders, there has been a recent call for evidence-based assessment (EBA). In line with this movement, an ADHD assessment strategy is presented that follows guidelines prescribed by Pelham, Fabiano, and Massetti (2005), and involves four assessment objectives: assessment for diagnosis (i.e., the categorical/psychiatric determination), assessment of impairment (i.e., specification of impaired domains of functioning), assessment for intervention planning, and outcome evaluation of treatment. Within these domains, several assessment methods are available. These procedures have been used in a traditional, diagnosis-driven approach to the assessment of ADHD; however, they are also appropriate for use in a dynamic and fluid problem-solving approach to assessment. These procedures are based on the Pelham et al. (2005) model, are consistent with the School Psychology Blueprint for Training and Practice III, and focus on the child’s areas of impairment at school, in peer relations, and in the family. The difference between what we prescribe and the traditional, diagnosis-driven assessment of ADHD does not involve a difference in methods selected, but a difference in the questions to be addressed throughout the assessment process. This method also allows for a more frequent examination of the assessment data informing decisions to remove interventions that are no longer necessary as well as those involved in exiting children from services. Table 1 presents a list of evidence-based methods for the assessment of ADHD. Although purposes may differ, many of the same assessment strategies are employed in both the RTI model and traditional models. Differences lie in the formality of the process through which levels of services and the method of special education eligibility are determined. If the intervention produces a desirable change in behavior at one of the lower tiers of intervention and returns the child’s behavior within normal limits, the child will no longer require intervention. If, however, the child progresses through the tiered model of research-based interventions, and significant progress is not apparent, the child may be a viable candidate for more intensive intervention, ultimately at the level of special education services. Thus, these methods allow for continuous hypothesis generation and testing throughout the process. It is important to note, that current law is not written in an RTI framework for the assessment of behavior disorders; however, this approach is expected for the assessment of learning disabilities, and many students with ADHD have learning disabilities. Therefore, we advocate that school psychologists move closer to an RTI approach as it pertains to assessment and intervention- planning for students with ADHD. As such, assessment data collected within the RTI framework may identify clear links to intervention targets and provide data regarding meaningful changes in children’s behaviors in response to assessment-based interventions. Assessing Attention-Deficit/Hyperactivity Disorder Using an RTI Approach Renée M. Tobin W. Joel SchneiderSteven Landau Table 1. Selected List of Evidence-Based Assessment Methods for ADHD Figure 1. An RTI approach to the assessment of ADHD in children MeasureRelevant references Narrow-band Behavior Rating Scales Conners’ Rating Scales-Revised (CRS-R) Conners (1997) ADHD-IV Rating Scale DuPaul, Power, Anastopoulos, & Reid (1998) Broad-band Behavior Rating Scales Child Behavior Checklist (CBCL) and Teacher Report Form (TRF) from the Achenbach System of Empirically Based Assessment (ASEBA) Achenbach & Rescorla (2004) Parent Report Form (PRS) and the Teacher Report Form (TRS) from the Behavior Assessment System for Children (BASC-2) Reynolds & Kamphaus (2004) Direct Observations Direct Observation Form McConaughy & Achenbach (2004) Student Observation System from the BASC-2 Reynolds & Kamphaus (2004) Individualized Target Behavior Evaluation (ITBE) Pelham et al. (2005) Functional Assessments No specific form DuPaul, Eckert, & McGoey (1997); Gresham, Watson, & Skinner (2001) Interviews Unstructured Parent Interview (no specific form)Barkley (2006); O’Neill et al. (1997) Source Tobin, R. M., Schneider, W. J., Reck, S. G., & Landau, S. (in press). Best practices in the assessment of children with attention-deficit/hyperactivity disorder: Linking assessment to response-to-intervention. To appear in A. Thomas & J. Grimes (eds.), Best Practices in School Psychology: Vol. V. Washington, D.C.: National Association of School Psychologists. Based on findings from over 30 years of research on the topic, Pelham and his colleagues (2005) provide guidelines for best practices in assessment of ADHD, and these guidelines map readily onto the RTI model. Using Pelham et al.’s suggestions, we align traditional and contemporary methods of assessment for ADHD with the current RTI approach, as shown in Figure 1.