Background To generate unbiased estimates for data collected using respondent-driven sampling (RDS), a number of assumptions need to be met: individuals recruit randomly from their social network and people can accurately report their eligible network size. However, research has shown that these assumptions are often violated.

Methods This study used baseline data from Crew 450, a longitudinal study of young men who have sex with men in Chicago who were recruited via a modified form of RDS and its network substudy, in which a subset of 175 participants reported details on the composition and characteristics of their social network at either 1 or 2 years postbaseline.

Results Nearly two-thirds of participants reported giving coupons to at least one alter (64%), and 56.3% believed their alter(s) used the coupons. Frequency of communication, closeness and type of relationship played a major role in determining coupon distribution. Participants whose alters used coupons were significantly less likely to describe the strength of their relationship as ‘not at all close’ (OR=0.08; 95% CI 0.02 to 0.36) compared with ‘very close’ and to communicate weekly (OR=0.20; 95% CI 0.08 to 0.49) or 1–6 times in the past 6 months (OR=0.18; 95% CI 0.06 to 0.59).

Conclusions Contrary to RDS assumptions, we found that relationship characteristics played a significant role when individuals decided to whom they would give coupons.