Participants, known collectively as Mission Indians, were recruited from eight geographically contiguous reservations with a total population of about 3,000 individuals. Participants were recruited using a combination of a venue-based method for sampling hard-to-reach populations (Kalton & Anderson 1986; Muhib et al. 2001) as well as a respondent-driven procedure (Heckathorn 1997). The venues included: tribal halls, health clinics, tribal libraries, and stores on the reservations. Fliers advertising the study were placed in each venue with the telephone number of the tribal recruitment coordinator. The venues were also regularly visited by the tribal recruitment coordinator who approached potential participants to offer information about and enrollment in the study. Approximately half of the participants were recruited using each method. A 10–25% rate of refusal using the venue method occurred depending on venue. The refusal rate in the respondent-driven procedure is not known. Potential participants contacted the tribal recruitment coordinator or the study coordinator at the research facility. At that time, interested participants were given a brief description of the study, told transportation would be provided, and informed as to the amount they
