Developing an Index of Peer Support Specialist Work Settings and Activities - PROJECT ABSTRACT Substance use disorder (SUD) and overdose deaths represent a national public health crisis. Recovery is the recommended outcome for individuals with SUD, however, access to treatment and recovery supports varies greatly across the U.S., and many who could benefit from them do not receive services in part due to stigma, difficulty navigating a complex service continuum, wait times, and costs. Peer support specialists (PSS) are individuals in recovery from a SUD who are trained, certified, and employed to assist and provide guidance to patients in various states of recovery. The prima facie practical value of peers in support roles is high, as they can engage individuals outside traditional boundaries and extend the reach of care beyond clinical settings. PSS lived experience may make them more relatable than other medical or social service staff. Moreover, peer support represents a mechanism that could advance long-term recovery at lower expense relative to services delivered by other licensed clinical personnel. Regrettably, the evidence for PSS services is relatively scant in part due to methods that are ill-fitted to measure the dynamic, behavioral, and interactive process of recovery across time and within a complex service continuum. Consistently, the existing literature points to the lack of a uniform taxonomy (job titles, service roles, job-related activities, work settings) as an impediment to advancing the research on PSS provider service. In response, the Developing an Index of Peer Support Specialist Work Settings and Activities study will identify the fundamental components of PSS service delivery providing the foundation for subsequent researchers to perform rigorous effectiveness research on the public health impact of PRSS service provision. The following Aims will be accomplished building upon two preliminary studies characterizing PSS work roles and activities: 1) conduct a psychometric review of Survey 2.0 and align survey constructs within a social ecological systems framework; 2) verify PSS work roles and activities within regional recovery networks; 3) authenticate the Peer Support Specialist (PSS) Work Settings and Activities Index. A dynamic team, jointly led by investigators and consultants within the Consortium on Addiction Recovery Science (CoARS) in collaboration with state and national PSS associations and credentialing bodies, offer assurance of the successful execution of these Aims. This proposed work is innovative as it seeks to shift the standard paradigm of research design and survey construction by engaging working PSS and researchers with lived experience of SUD in the co-creation of survey instruments grounded in social ecological system theory. The proposed work is significant as it addresses a key barrier to the accurate assessment of PSS service. Results will open the door for high-quality scientific exploration into the effectiveness of PSS service provision and inform the effective deployment of PSS interventions across regional service systems.