“…Traditional methods of sampling, such as address-based sampling (ABS) and random digit dialing (RDD), may be ineffective when listings are inaccurate or unavailable, and when the population is highly mobile (Lavelle et al, 2009). These sampling techniques allow researchers to recruit populations that are hard to identify and access, especially in contexts where cultural groups are distrustful or suspicious of outside researchers (e.g., Lavelle et al, 2009;Shoultz, Oneha, Magnussen, Hla, Brees-Saunders, Cruz et al, 2006). To overcome these challenges, other sampling techniques may be used, such as obtaining address lists from a service provider (e.g., Duffy, Goldberg, & Buchwald, 2006), using time-space sampling (e.g., Stueve et al, 2001), or snowball, chain-referral, and respondent-driven sampling (RDS) techniques (Faugier & Sargeant, 1997;Heckathorn, 2007; see also Part IV of this volume).…”