This study examines the political participation of undocumented Mexican immigrants residing in the United States in Mexican external voting. As international mobility of people has increased globally, scholarly attention has grown concerning how overseas citizens engage in electoral processes in their countries of origin. However, previous studies based on traditional survey methods may have yielded biased results due to the underrepresentation of undocumented immigrants, who are less likely to enroll in survey company panels due to concerns about the potential compromise of their identities. To include this hard-to-reach population and conduct representative sampling, our research employs a method called respondent-driven sampling (RDS), which permits the surveying of a population devoid of a sampling frame. Our analysis of the Mexican case demonstrates that a lack of electoral information, lower levels of education, and heightened distrust of the Mexican government are associated with diminished electoral participation.

Latinos constitute a hard-to-reach minority population in Iowa. We used respondent-driven sampling (RDS) to supplement random digit dialing to recruit Latinos for a community physical activity intervention. RDS yielded a 59% increase in Latino participation in just 2 months, with few demographic differences between RDS and random digit dialing groups. RDS may increase recruitment of underrepresented populations and strengthen community engagement; however, it is not a quick fix for underperforming recruitment methods.

Respondent-driven sampling (RDS) is frequently used when sampling from hidden populations. In RDS, sampled individuals pass on participation coupons to at most c of their acquaintances in the community (c = 3 being a common choice). If these individuals choose to participate, they in turn pass coupons on to their acquaintances, and so on. The process of recruiting is shown to behave like a new Reed–Frost-type network epidemic, in which 'becoming infected' corresponds to study participation. We calculate R0, the probability of a major 'outbreak', and the relative size of a major outbreak for c < ∞ in the limit of infinite population size and compare to the standard Reed–Frost epidemic. Our results indicate that c should often be chosen larger than in current practice.

Drawing on the original data collected during a period of university student protest in Greece, we explore whether the expected gains from the act of protesting itself influence an individual's decision to participate in collective action. More particularly, we investigate the extent to which the process incentives qualify the weight individuals attach to the primary elements of the original cost–benefit equation of rational choice theory as well as other considerations in their decision-making process. Our findings point out that the magnitude of the effect of the process incentives is very strong and its inclusion in a rational choice model improves our understanding of students’ participation in protest activities. Turning to indirect effects, we show that process incentives behave as a first stage precondition for the students’ decision to participate in collective action. In the absence of perceived benefits associated with the process of protesting, the importance of attaining the public good becomes much less important in their decision-making process.