PROJECT SUMMARY/ABSTRACT People experiencing homelessness (PEH) are at exceptionally high risk of frequent emergency department (ED) and hospital use, poor functional outcomes, and increased morbidity and mortality from poorly managed chronic health conditions and complex social needs. Significant deficiencies in continuity of care and poor communication between PEH and health and social services providers contribute to these bleak long-term outcomes. Evidence-based interventions of particular promise for reducing ED and hospital utilization and improving health outcomes and meeting social needs involve: 1) providing care in the community to overcome barriers including transportation and fear of stigmatization; 2) coordination of care transitions following ED or hospital discharge to improve access to needed community supports and reduce the risk of readmission; and 3) using mHealth technology to link PEH with appropriate community-based health and social services. This project will build on evidence from two feasibility studies in order to integrate and test a mHealth intervention, comprised of global positioning system technology and text messaging components, into a community setting to connect PEH with a community-based case manager and healthcare and social services. Our hypothesis is that integrating the mHealth intervention into an established, trusted navigation center for PEH will mitigate barriers to care and gaps in the care continuum resulting in decreased ED and hospital use and improved health outcomes and attainment of social needs. Our specific aims are to: 1) refine the existing mHealth intervention and implementation strategy using a community-based participatory research approach; 2) conduct a stratified RCT to compare a mHealth intervention with usual care community-based case management to examine the impact on healthcare utilization (primary outcome), medication adherence, social support, psychological distress and social needs attainment (secondary outcomes) in PEH; and 3) identify and understand factors from PEH and stakeholder perspectives that impact sustainability of the mHealth intervention. The project will be conducted in four phases. During phase one, we will refine the intervention (Aim 1) by eliciting feedback from PEH, key informants, and our community advisory board before conducting a usability test of the refined mHealth intervention. Phase two will consist of the RCT (Aim 2) to compare the efficacy of the mHealth intervention to a usual care control group. Phase three will identify factors to facilitate sustainability of the mHealth intervention (Aim 3) using stakeholder interviews. Phase four will consist of data analysis, triangulation of findings, and dissemination. This study is significant and innovative for several reasons: targets an AHRQ understudied group with complex needs and use of high cost services at a critical transition point; is based in a community-based navigation center instead of a tradi...