The goal of this project is to improve methods for establishing and maintaining trust between providers and individuals in vulnerable populations across a diverse set of programs and practices. The project will examine the effectiveness of a mobile app that facilitates constructive dialogue between patients or clients and service providers in building trust and achieving positive health outcomes. This work is grounded in research around the concept of “working alliances” in which the creation of healthy alliances defined by mutual respect, appreciation, and trust between providers and individuals in care is associated with more positive health outcomes. The grantees will study (1) whether a client feedback mobile app improves trust between providers and clients; and (2) whether clients reporting high levels of trust with providers achieve superior behavioral health outcomes compared to those reporting low levels of trust. Deliverables will include a project work plan, annual and final narrative reports, and financial reports. The grantees will also produce scientific papers for peer-reviewed publication, oral presentations, and social media posts.