Table 1. Screening inclusionary and exclusionary criteria.

Inclusion	Exclusion
Qualitative or quantitative empirical studies	Not published in English
United States-based	Only discusses peers who are in ‘sponsorship’ positions within substance use mutual aid organizations or people with lived experience working in a professional position (e.g., administrator, addiction counselor, social worker, therapist)
Discusses peer recovery support services (PRSS) in the area of substance use harm reduction, treatment, or recovery	Discusses peers who work outside the substance use and harm reduction fields (e.g., mental/physical health, etc.)
Discusses certified and uncertified peers who are employed or in volunteer positions as well as people who use drugs (PWUD) who serve as peers
Discusses workforce outcomes
Published between 1/1/1999 to 8/1/2023

List of inclusionary and exclusionary criteria for screening identified literature.