Content validity evidence for the Verbal Behavior Milestones Assessment and Placement Program.
Autism spectrum disorder (ASD) affects one in 54 children in the United States and the prevalence has increased by exponentially in the last decade (Centers for Disease Control and Prevention [CDC]). With the rising prevalence, evidence-based treatment is critical for this population. Interventions based in applied behavior analysis (ABA) are the most effective research-based strategies for individuals with ASD (Axelrod, McElrath, & Wine, 2012; Foxx, 2008; Lovaas, 1987). In order to develop optimal treatment plans with accurately identified goals and intervention strategies, individuals must undergo a comprehensive assessment that includes the use of research-based instruments. The Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP) is the most widely used instrument for curriculum development and treatment planning in the field of ABA. However, there is currently no validity or reliability studies to support its widespread use. The purpose of this study is to address this gap in the literature by providing content validity evidence for the VB-MAPP. A national panel of 13 subject matter experts (SMEs) provided an evaluation of the domain relevance, age appropriateness, method of measurement appropriateness, and domain representation across the three levels of the Milestones Assessment, Early Echoic Skills Assessment (EESA), and the Barriers Assessment. Overall, the content validity evidence for the VB-MAPP Milestones, EESA, and Barriers Assessment was moderate to strong across the evaluated areas although there were areas with limited or conflicting support. The evidence suggests that the scores of the VB-MAPP provide information relevant to the target behaviors of interest but a few domains may not be fully represented by their specific items. When the VB-MAPP is used by itself, researchers and practitioners can have reasonable confidence in the results for many domains but should exercise caution for some domains across levels. That said, it is recommended that the VB-MAPP be used in conjunction with other sources of assessment information, which is recommended for assessment in general. The results of this study could inform revisions to future editions of the VB-MAPP. With some targeted revisions, the VB-MAPP could serve as a comprehensive assessment with strong validity evidence for this developmental age range.