Multilevel confirmatory factor analysis was used to evaluate the factor structure underlying the 12-item, three-factor Interagency Collaboration Activities Scale (IACS) at the informant level and at the agency level. Results from 378 professionals (104 administrators, 201 service providers, and 73 case managers) from 32 children's mental health service agencies supported a correlated threefactor model at each level and indicated that the item loadings were not significantly (p < .05) different across levels. Reliability estimates of the three factors (Financial and Physical Resource Activities, Program Development and Evaluation Activities, and Collaborative Policy Activities) at the agency level were .81, .60, and .72, respectively, while these estimates were .79, .82, and .85 at the individual level. These multilevel results provide support for the construct validity of the scores from the IACS. When the IACS was examined in relation to level-1 and level-2 covariates, results showed that participants' characteristics (i.e., age, job role, gender, educational level, and number of months employed) and agency characteristics (i.e., state location and number of employees) were not significantly (p > .05) related to levels of interagency collaboration.Interagency collaboration has been defined broadly as "mutually beneficial and well-defined relationships entered into by two or more organizations to achieve common goals" (Mattessich, Murray-Close, & Monsey, 2001, p. 4). Additional defining characteristics of interagency collaboration have included: (a) developing and agreeing to a set of common goals and directions, (b) sharing responsibility for obtaining those goals, and (c) working together at all levels of an organization to achieve those goals (Bruner, 1991;Cumblad, Epstein, Keeney, Marty, & Soderlund, 1996).In the past two decades, the call for collaboration among child-serving organizations has increased as many believe that important problems faced by children that result from being served by multiple agencies (e.g., service fragmentation, gaps, barriers) cannot be resolved effectively by single entities working alone (Bergstrom et al., 1995; Mattessich et al., 2001;Salmon, 2004). For example, recent reforms in children's mental health service delivery, such as the systems of care approach, have emphasized interagency collaboration as an important element in providing comprehensive services to children with serious emotional disturbance (Stroul & Friedman, 1986). Interagency collaboration may provide a way to cope with increasing complexity; meet expanding expectations, needs, and demands of human services; maximize human resources; share facilities and program resources; and improve utilization of funds and personnel (Jones, Thomas, & Rudd, 2004;Lippitt & Van Til, 1981).While many agree about the value of interagency collaboration, others have identified potential negatives associated with interagency collaboration. These negatives include diffusion of responsibility, reduced service quality, and e...