Researchers are often interested in studying vulnerable and stigmatized groups using survey research methods. This may arise from purely academic interest in human behavior and its motivations, from a concern about the safety and well-being of these groups, or from a concern about the risks these groups may pose for others. Interest in these groups may take several forms. One is the estimation of the size of the group – how many are there? A second is from an interest in how policies affect them, such as whether the public health system addressees their needs. A third is how policies might be enacted to change their behavior, in particular, to discourage behaviors that are dangerous to themselves or others, such as sexual risk behaviors. For example, there was longstanding interest in sex workers among academics that took on new significance with the onset of the AIDS epidemic. Suddenly, they were viewed not only as an interesting subculture, but also as a group that was vulnerable for HIV infection and a potential route of transmission for HIV from drug users to the general population. This resulted in a burst of interest in studying them systematically that posed new methodological challenges (Kanouse, Berry, Duan, Lever, Carson, Perlman et al., 1999).
For the purposes of this chapter, we consider vulnerable and stigmatized populations to be groups that if publicly identified might (May-Chahal & Cawson, 2005) be subjected to shame, scorn, ridicule, or discrimination in their interactions with others (Amstadter, McCauley, Ruggiero, Resnick, & Kilpatrick, 2008), suffer damage to financial standing, employability, or reputation within the community (Kanouse, Berry, Gorman, Yano, & Carson, 1991), be subject to legal sanctions including criminal penalties, civil liability, or administrative actions (Ross, Timpson, Williams, Amos, McCurdy, Bowen et al., 2007), or be subject to persecution, threats, or reprisals as a result of research participation. These groups might include, for example, drug users and dealers; sex workers, pimps and sex traffickers; victims of sexual assault, sexual harassment or domestic violence and the perpetrators of these acts; sexual minorities, such as “swingers” or child molesters; people with stigmatizing medical conditions or who have had socially sanctioned medical procedures, such as abortions; and people who have committed crimes, such as driving under the influence or failing to pay child support.