Table 1 Scoping review inclusion and exclusion criteria

Articles were included if they:

1. Measured population need for substance use services using expert-defined (use prevalence, diagnostic prevalence, service utilization) and/or consumer-defined measures (perceived need, barriers to care, or help-seeking from family and friends); and

2. Recruited samples from community settings; and/or

3. Outlined one or more methods for assessing population need for substance use services or estimating required substance use service system capacity; and/or

4. Reviewed literature on methodological or conceptual issues in assessing population need for substance use services.

Articles were excluded if they:

1. Described need for substance use services exclusively amongst treatment-seeking or clinical samples; or

2. Described need for services not intended to mitigate substance use disorders/problematic use directly (e.g. Hepatitis C treatment, HIV prevention programs, dental care); or

3. Described service needs among populations experiencing mental disorders only (i.e. excluded substance use disorders); or

4. Were effectiveness or cost-effectiveness studies; or

5. Narratively summarized empirical findings of previous research on population need for substance use services.