PROJECT SUMMARY /ABSTRACT Motivational interviewing (MI) is a leading evidence-based practice (EBP) for substance use disorder (SUD) with potential to improve population health. Although disseminated widely, MI fidelity and sustained use remain low among community providers. Strategies are needed to improve the reach and impact of EBPs in usual care. Implementation strategies related to improving the organizational context of SUD treatment programs may lead to improved MI implementation. Improving an organization’s EBP implementation climate, the shared perception of the importance of EBP implementation within an organization, can promote provider implementation outcomes. EBP implementation climate is cultivated by program leaders who exhibit behaviors that support implementation; thus, interventions, such as the Leadership and Organizational Change for Implementation (LOCI) intervention, are being evaluated for their impact on provider MI implementation outcomes. A presumed mechanism of LOCI is organizational vertical alignment, which is the extent to which leaders and staff share perceptions about EBP implementation climate. Vertical alignment between leaders and providers regarding implementation climate can signal shared views about the importance of the EBP, and shared views that the structures and processes set in place by leaders facilitate implementation on the front lines. However, analyses have yet to quantitatively examine this mechanism, with research typically indexing mean level perceptions of front-line providers, without considering the impact of variation or provider alignment with leader perceptions. Additionally, it is yet unknown whether vertical alignment is sensitive to change over time and with exposure to leadership intervention. These data are critical to establishing vertical alignment of implementation climate perceptions as a potential mechanism of action of implementation strategies. The objective of this NRSA application is to foster my development as an implementation scientist with a focus on organizational behavior, leadership, and addiction health services. This proposal leverages data from a NIDA funded cluster randomized trial that examined the effect of LOCI on implementation leadership and climate and MI implementation outcomes. The proposed project will examine organizational vertical alignment of perceived implementation climate as a potential mechanism of action of organizational implementation strategies. Specifically, Aim #1 will measure vertical alignment in perceived implementation climate among providers and leaders in SUD treatment clinics implementing MI. Aim #2 will identify clinic characteristics that are correlated with vertical alignment at baseline. Lastly, Aim #3 will examine longitudinal trajectories of vertical alignment in perceptions of implementation climate and their associations with MI implementation outcomes. The present study represents an important step in further understanding mech...