Table 13.

Engaging non-traditional populations and contexts

Sub-category	Code	Description	Contributing articles
Engaging non-traditional populations and contexts (n = 30)	Marginalised and vulnerable Groups (n = 14)	Recommends developing broad and representative outreach strategies to maximise inclusion of individuals and communities affected by structural disadvantage or social exclusion	[6, 10, 11, 21, 24, 25, 32, 37, 40, 43, 48, 50, 57, 58]
	Proxy and developmental interest-holders (n = 12)	Recommends considering inclusion of family members, caregivers, or others speaking on behalf of those unable to participate directly (e.g. young children, cognitively impaired individuals)	[24, 26, 30, 32–34, 37, 38, 49, 53, 55, 58]
	Diverse and global contexts (n = 19)	Recommends maximising regional, cultural, and economic diversity in participants to address structural inequality; recommends ensuring outreach strategies incorporate varied geographic and socioeconomic settings including LMIC contexts	[11, 20, 21, 24, 25, 32, 37, 39, 40, 42, 44, 49, 50, 52, 54–56, 58, 60]