Table 1.

SIPP study objectives and components

SIPP objective	Study component
1. Build peer-network research capacity and explore whether the quality and impact of their SIPP engagement with PWUC differs in comparison with SIPP engagement through drug treatment services	Peer network
	Process evaluation; Impact evaluation
2. Measure the effect and cost-effectiveness of the SIPP kit on harms and risks associated with crack use (pipe sharing, presentation at drug services, using homemade pipes, cuts/burns, crack injecting)	Impact evaluation; economic evaluation
3. Evaluate SIPP fidelity, reach and acceptability in diverse specialist drug service and peer-network settings	Process evaluation
4. Explore the barriers and facilitators to SIPP uptake and service engagement among PWUC	Process  evaluation
5. Explore the mechanisms through which SIPP facilitates changes in health risks and access to services, and how these are shaped by local contextual factors	Process evaluation
6. Co-develop a scalable SIPP toolkit and harm reduction resources to enhance PWUC engagement with specialist drug services and to facilitate crack-related risk reduction practices	Peer network
7. Translate evidence to policy and advocacy outputs, including to inform legislative review	All components