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Needs assessment in hidden populations using respondent-driven sampling

One of the primary methods for identifying relevant evaluative criteria or dimensions of merit for evaluating programs is assessing the needs of a program's target population. These criteria, or dimensions, are the attributes of the evaluand, which are used for determining how good or how effectively a program is meeting the target population's needs. However, identifying relevant criteria for many human and social service programs, especially those serving hidden populations (e.g. injection drug users, HIV-positives, homosexuals, prostitutes, and the homeless), poses numerous practical and methodological challenges. Using a case study approach, this article describes how Heckathorn's (1997) respondent-driven sampling (RDS) was used to access and draw estimates from the homeless population in a mid-sized urban community in the United States as part of an evaluation that included assessing the population's performance needs, gathering baseline data, and as one source for identifying the relevant criteria by which the program was evaluated.