Contents lists available at ScienceDirect Children and Youth Services Review journal homepage: www.elsevier.com/locate/childyouth A systematic review of the efectiveness of interagency and cross-system collaborations in the United States to improve child welfare outcomes Ijeoma Nwabuzor Ogbonnaya ⁎ , Annie J. Keeney School of Social Work, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-4119, USA ABSTRACT The purpose of this systematic review is to summarize the efects of interagency and cross-system collaboration aimed to improve child welfare-involved children and family outcomes related to safety, permanency, and well-being. We conducted a comprehensive search to identify studies that evaluated interagency/cross-system child welfare collaborations, resulting in 11 studies selected for inclusion. The analysis included narrative and meta-analysis approaches. All selected studies focused on substance use; our search criteria did not identify any interagency collaborations related to other co-occurring conditions, such as domestic violence and mental health. Results from both narrative and meta-analyses revealed family drug treatment court (FDTC) collaboration intervention was positively associated with the entry (OR = 2.935, 95% CI [1.498, 5.753]) and completion (OR = 2.074, 95% CI [1.263, 3.406]) of substance use services. Additionally, FDTC (OR = 2.401, 95% CI [1.751, 3.292]) and recovery coaches (OR = 1.522, 95% CI [1.166, 1.987]) were positively associated with likelihood of reunifcation. Narrative and meta-analysis results related to the relationship between FDTC and days to reunifcation were less positive across studies (g = 0.470, 95% CI [0.247, 0.694]). Thus suggesting, although FDTC may positively infuence the likelihood that children are reunifed with their families in the future, this intervention may have less infuence on how quickly families achieve the reunifcation process. We found positive client outcomes regardless if there existed a lower (co-ordination) or higher (integration) level of collaboration, demonstrating positive collaboration outcomes may occur using limited child welfare resources. This systematic review can beneft child welfare practitioners, policymakers, and families in selecting the most appropriate and efective interagency/cross-system substance use services. We discuss re- commendations for future research. 1. Introduction Many families involved with child welfare are also afected by issues related to domestic violence, substance use, behavioral/mental health, physical health, criminal justice involvement, education, and poverty (Courtney, McMurtry, & Zinn, 2004; Landsverk, Garland, & Leslie, 2002; Malmgren & Meisel, 2004; Ogbonnaya & Kohl, 2018; Rubin, Alessandrini, Feudtner, Localio, & Hadley, 2004; Trout, Hagarman, Casey, Reid, and Epstein, 2008;Young, Boles, & Otero, 2007). These co- occurring issues demonstrate the need for child welfare to collaborate with other agencies and systems in order to increase positive outcomes for the children and families they serve. As such, federal policy has mandated interagency and cross-system collaboration to improve child welfare services and outcomes (Ehrle, Scarcella, & Green, 2004; “Fostering Connections” P.L. 110–351, 2008). However, researchers have not systematically assessed efects of such collaborations on child welfare outcomes. The purpose of this study is to systematically sum- marize research related to the efectiveness of interagency and cross- system collaborations with child welfare. We hope that child welfare practitioners, researchers, and policymakers can use this information to identify promising practices for delivering interdisciplinary services and interventions to child welfare-involved families. 1.1. Models of collaboration According to Horwath and Morrison (2007), collaborative partner- ships in children's services may exist along a continuum that ranges from communication (informal and local) to integration (formal and whole agency). Specifcally: 1. Communication: individuals from diferent disciplines talking to- gether. 2. Co-operation: low-key joint working on a case-by-case basis. 3. Co-ordination: more formalized joint working, but no sanctions for non-compliance. 4. Coalition: joint structures sacrifcing some autonomy. 5. Integration: organizations merge to create new joint identity (Horwath & Morrison, 2007, p. 56). The highest level of collaboration is integration. Integrated service collaborations include features such as joint training, budget, staf, and decision-making; single assessment; consolidated management system; shared goals and targets; common governance; and mandate for colla- boration (Horwath & Morrison, 2007). https://doi.org/10.1016/j.childyouth.2018.10.008 Received 20 June 2018; Received in revised form 5 October 2018; Accepted 6 October 2018 ⁎ Corresponding author. E-mail address: iogbonnaya@sdsu.edu (I.N. Ogbonnaya). Children and Youth Services Review 94 (2018) 225–245 Available online 10 October 2018 0190-7409/ © 2018 Elsevier Ltd. All rights reserved. T