Sampling in difficult to access refugee and immigrant communities.

We evaluated sampling strategies and trust-building activities in a large multiphase epidemiologic study of torture prevalence in populations that were difficult to locate and enroll. Refugee groups under study were Somalis from Somalia and Oromos from Ethiopia who were living in Minneapolis and St. Paul, Minnesota, in 1999-2002. Without a complete sampling frame from which to randomly recruit participants, we employed purposive sampling methods. Through comparative and statistical analyses, we found no apparent differences between our sample and the underlying population and discovered no effects of recruiting methods on study outcomes, suggesting that the sample could be analyzed with confidence. Ethnographic trust and rapport-building activities among investigators, field staff, and immigrant communities made it possible to obtain the sample and gather sensitive data. Maintaining a culture of trust was crucial in recovering from damaging environmental events that threatened data collection.