Background: The overall impact goal of the Optimizing Function and Independence QUERI program (“Function QUERI”) is to improve VA care by implementing and evaluating evidence-based clinical programs (EBPs) to maximize function and independence in vulnerable Veterans. Since its inception in 2016, Function QUERI has supported implementation of three EBPs to optimize function and independence: group physical therapy for knee osteoarthritis (Group PT), supervised walking for hospitalized older adults (STRIDE) and caregiver skills training (Caregivers FIRST). These EBPs have demonstrated positive effects for both Veterans and their families. Building on successful partnerships with national and VISN partners and incorporating lessons learned, in the next 4 program years (October 2021-September 2025), Function QUERI will advance each EBP to the next phase of implementation at additional sites. Group PT was evaluated as a quality improvement program (QI) at one VA medical center (VAMC), and we will now implement and evaluate this program at 16 sites. STRIDE and Caregivers FIRST have each been implemented in 8 VAMCs in ongoing clinical trials and have now been endorsed by VA program offices for national dissemination; thus, we have the unique opportunity and capability to develop and test prototype approaches for taking EBPs to national scale in VA. Methods: Adopting new EBPs requires buy-in and cooperation among many different service lines, and a ‘one- size’ fits all approach to getting programs implemented is rarely effective. Therefore, as Function QUERI meets our primary goal of spreading EBPs to optimize Veteran function and independence we will also conduct rigorous evaluations to understand how evidence-based implementation strategies can best support the adoption of complex interventions and maximize their sustainability. First, Function QUERI will advance understanding and application of implementation strategies that promote adaptability of clinical programs to fit local environments and build skills among implementation teams. Second, across EBPs, we will monitor sites’ implementation progress and test the impact of adding higher intensity implementation strategies at sites with low adoption of the EBP. In this way, Function QUERI will fill a critical knowledge gap of how to optimize use of implementation strategies on a national scale. We will accomplish Function QUERI’s overall goals through the following specific aims: 1) Implement 3 EBPs that have been recognized by VA leaders as high priority programs to fill quality gaps for Veterans at risk for functional decline or disability and their family caregivers; 2) Assess EBP impact on quality metrics and conduct business case analysis to inform sustainment; 3) Advance application of implementation strategies by testing implementation intensification approaches across EBPs; 4) Partner with VA leaders to conduct rapid, high-quality implementation and evaluation projects to inform decisions o...