ASD and Nordoff-Robbins Music TherapyCommunication and social interaction competencies are core deficits experienced by children with autism (Joseph & Tager-Flusberg, 2009). Understanding the extent of these defi- cits and how children respond to therapy is important not only in demonstrating progress in a single session, but also in map- ping the course of change over time. Further, as many chil- dren with autism receive music therapy in groups, developing a tool that can be used in a group setting may be advantageous for therapists and researchers.Nordoff-Robbins (NR) Music Therapists have worked with children with autism for decades, developing and refining inter- ventions to maximize each child's social and communicative skills, within the core framework of improvisational musical experiences (Aldridge, Gustorff, & Neugebauer, 1995; Guerrero & Turry, 2013). While indexing has been a core part of this pro- cess, in which NR therapists review videos of each therapy ses- sion (Nordoff & Robbins, 2007), Paul Nordoff and Clive Robbins (1977), also developed evaluative scales to document music therapy sessions quantitatively (Mahoney, 2010; Nordoff & Robbins, 2007; Trevarthen, Aitken, Papoudi, & Robarts, 1998).Building upon this foundation, NR clinicians and research- ers identified a need to develop a new scale with better- defined constructs that expand upon the core concepts of the original scales. The Music Therapy Communication and Social Interaction scale, abbreviated to the (Guerrero et al., 2014), was designed to provide a method of measuring behav- iors perceived as either communicative or socially interactive that are commonly elicited during a music therapy session. It resembles most closely Scale II, Musical Communicativeness, from the original scales. (see Appendix A: MTCSI - Group)Developing the MTCSICreating the occurred in multiple, sequential stages, commencing with identifying behaviors associated with com- munication and social interaction that could be observed and evaluated using a video recording. Since its opening in 1990, therapists at the Nordoff-Robbins Center have amassed a wealth of clinical experience interacting with young chil- dren with ASD. This pooled resource was drawn upon to draft the domains that constitute the MTCSI, namely the elemental construct of engagement, which is defined by behaviors asso- ciated with social interaction and communication.Guerrero et al. (2014) theorized that in a controlled experi- mental study, a music therapy intervention would demonstra- bly improve the deficit behaviors associated with ASD, which they identified principally as communication and social interaction. According to Joseph and Tager-Flusberg (2009), Autism is diagnosed solely on the basis of behavioral impair- ments and anomalies, specifically in the three core symptom domains of reciprocal social interaction, communication, and repetitive interests and activities (p. 201). Further, Tsatsanis (2005) likens the behavioral traits of autism with those of peo- ple with prefrontal cortical damage: These characteristics include response preservation, disinhibition, narrow range of interests, failure to plan, difficulty taking the perspective of others, and lack of self-monitoring (p. 372). Taken together, the existing findings from ASD research inside and outside of music therapy contexts provide firm foundational support for the theoretical structure of the MTCSI, an elemental block of establishing content validity.The second step involved operationalizing the behav- iors attributed to communication and social interaction and the rating scale proposed to assess them. Table 1 details the organizational structure of the MTCSI. For a detailed descrip- tion of each construct measured by the MTCSI, please refer to Appendix A.The first category is Engagement, or in its absence, Preengagement. Engagement is exhibited by communica- tion and/or social interaction with peers or the therapists. …