Reliability and validity measures for the VB-MAPP

Two measures of reliability on administering the VB-MAPP can be found in the paper by Barnes, Mellor, & Rehfeldt (2014) titled “Implementing the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP): Teaching Assessment Techniques.” These authors examined the administration of the VB-MAPP by two school psychologists under two conditions. In the first condition the psychologists, who had no history of administering the VB-MAPP, read the administration manual then administered the assessment. The second condition was conducted following additional training using a VB-MAPP behavior skills training (BST) package consisting of 5 components: instructions, modeling, rehearsal, feedback, and remedial teaching. Administration performance was measured on a 35-item checklist based on the information in the VB-MAPP administration guidelines. The results showed just reading the manual alone resulted in an average administration score of 57% on the checklist, with an interobserver agreement (IOR) score of 83%. Reading the manual and obtaining specific training with a BST package produced an average administration score of 92%, with an IOR score of 86%. Thus, VB-MAPP administration performance is clearly enhanced through additional hands-on training involving instructions, modeling, rehearsal, feedback, and remedial teaching. And the reliability measures on test administration were consistent across the two different levels of staff skills.

 

Barnes, C. S., Mellor, J. R., & Rehfeldt, R. A. (2014). Implementing the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP): Teaching assessment techniques. The Analysis of Verbal Behavior, 30, 36-47.

 

Two types of validity measures on the VB-MAPP have been published in the literature. External validity between the VB-MAPP and the assessment program Promoting the Emergence of Advanced Knowledge Relational Training System (PEAK) was examined by Dixon, Belisle, Stanley, Rowsey, Daar, & Szekely (2015). These authors found that “The results of a Pearson correlation suggest that there is a strong relationship between the two assessments (r=0.8266, p<0.0001), and that total scores on the VB-MAPP are a strong predictor of total scores on the PEAK-combined (R2=0.6833)” (p. 228). Dixon, Carmen, Tyles, Whiting, Enoch, & Daar, (2014) also demonstrated acceptable external validity measures between the PEAK and the Peabody Picture Vocabulary Test, providing additional indirect validity support for the VB-MAPP.

 

Construct validity and reliability for the intraverbal section of the VB-MAPP was demonstrated in a study by Sundberg and Sundberg (2011). In this study 39 typically developing children between the ages of 23 and 61 months old were assessed on an 80 item intraverbal subtest, and their results were compared to those of 71 children with autism on the same subtest. Reliability measures on the scoring of the intraverbal responses across both groups averaged 93%. The results demonstrated that the performances of typically developing children reflected the gradual increase in the difficulty of the intraverbal items and their chronological age. The scores of children with autism followed a similar pattern, but age was not the best predictor of performance, rather, the presence of pre-requisite verbal skills was a better indicator of intraverbal performance. The authors concluded, “The current data suggest that the intraverbal repertoires of typically developing children can provide a guide for intraverbal assessment and intervention for individuals with language delays” (p. 37). The results of this study were used as a basis for sequencing the skills in the intraverbal domain of the VB-MAPP.

Dixon, M. R., Belisle, J., Stanley, C., Rowsey, K., Daar, J. H., & Szekely, S (2015). Toward a behavior analysis of complex language for children with autism: Evaluating the relationship between PEAK and the VB-MAPP. Journal of Developmental and Physical Disabilities. 27, 223-233.

Dixon, M. R., Carmen, J., Tyles, P. A., Whiting, S. W., Enoch, M., & Daar, J. H. (2014). PEAK relational training system for children with autism and developmental disabilities: Correlation with Peabody Picture Vocabulary Test and assessment reliability. Journal of Developmental and Physical Disabilities, 26, 603-614.

Sundberg, M. L., & Sundberg, C. A. (2011). Intraverbal behavior and verbal conditional discriminations in typically developing children and children with autism. The Analysis of Verbal Behavior, 27, 23–43.