Randomization, Blinding, and Recruitment
Potential neighborhoods were identified in Khayelitsha and Mfuleni using analyses of local maps and having field workers collect data regarding each neighborhood. Neighborhoods were matched by UCLA based on housing type (percentage of formal/informal housing), density of shebeens (alcohol bars), and availability of electricity, water and sanitation. Neighborhoods were separated by buffer areas of at least 1-km or natural barriers such as highways, railways or rivers. Each neighborhood contained approximately 450–600 households, which we found had a median of 45–50 young men aged 18–29 years per cluster. Neighborhoods were recruited in triplets, i.e. three neighborhoods were enrolled and assessed concurrently. The UCLA team randomized neighborhoods into the CC or the SL intervention conditions with a 2:1 ratio.In each neighborhood, recruiters were young, local men from nearby neighborhoods (to prevent gossip) without a history of violence or arrests and good social skills. Recruiters went from dwelling-to-dwelling and randomly selected the first household (by flipping a coin on a hardcopy neighborhood map, with a supervisor) to enter and then systematically approached houses in concentric circles until approximately 45–50 young men were identified per neighborhood, met eligibility criteria, and provided voluntary informed consent. Assessment staff were blinded to study condition and the refusals to participate were very low (< 5% per neighborhood).