This article summarizes the main elements, advantages, and disadvantages of Respondent-driven Sampling (RDS). Some criticisms regarding the feasibility of the inherent assumptions, their point estimators, and the obtained variances are pointed out. This article also comments on the problems observed in the quality of reports. Surveys using RDS should be methodologically sound as they are being applied to define priorities in health programs and develop national and international policies for financing service delivery, among other uses. However, there is considerable potential for bias related to implementation and analytical errors. There is limited empirical evidence on how representative the results obtained by RDS are, and the quest to improve the methodology is still in progress. Nevertheless, to have confidence in RDS results, we must verify that the social structure of the networks conforms to the assumptions required by the theory, that the sampling assumptions are reasonably fulfilled, and that the quality of the report is optimal, particularly for methodological and analytical items.

The increasing migration phenomenon and its impact on sexual health highlight the urgency of improving access to preventive services and developing responsive surveillance mechanisms. This study aims to describe the context and define the implementation circuits of a Community-Based Surveillance System (CBSS) focused on social epidemiological aspects related to sexual health in Chile’s migrant population. A two-phase qualitative design was employed: Phase 1 involved formative research, and Phase 2 focused on the design of CBSS implementation circuits. The formative phase led to the selection and characterization of three community-based organizations (CBOs)—two in Santiago and one in Antofagasta—and two primary healthcare centers (PHCs). Findings revealed heterogeneity in institutional capacities, limited coordination between CBOs and the health system, and a high level of willingness to participate. PHCs showed comparable profiles. Based on this, differentiated operational circuits were co-designed and adapted with stakeholders, and formalized through site-specific implementation manuals. This pre-implementation evaluation helped identify critical contextual barriers and generate tailored strategies for CBSS deployment. The active involvement of local actors is essential to ensuring the contextual relevance, institutional acceptability, and future sustainability of the proposed model. These insights offer transferable learning for the design of health interventions in underserved and structurally constrained settings.

In the last decade, Chile has emerged as a receiving country for migrants from Latin America and the Caribbean (LAC). The scale of this phenomenon has sparked increasing interest in understanding its impact on various sectors such as healthcare and education. This study aims to characterize the scientific evidence and official reports on international migration toward Chile from 1990 to 2024. A scoping review was conducted. Global inclusion criteria: These encompassed articles and official reports published between 1990 and 2024 focusing on the migrant population toward Chile. Databases for the articles: These included PubMed, Scopus, WoS, and SciELO. Keywords: These included Transients and Migrants, Emigration and Immigration, Population Dynamics, Human Migration, Chile, South America, Latin America, and Freedom of Movement. Sources for the official reports: These included National Statistics Institute (INE for its acronym in Spanish); Department of Immigration and Foreign Services; Jesuit Migrant Service; National Human Rights Institute (INDH for its acronym in Spanish); and The UN Refugee Agency (UNHCR). No keywords were used. Global variables: These included type of study, sociodemographic characteristics, type of migration, object of study, main results, limitations, and conclusions. A concordance test of the questionnaire was conducted for the articles and official reports, yielding 91 % and 94 % agreement between observers, respectively. Accordingly, 21 articles and 28 official reports were included. In both types of sources, the study population included the entire life cycle, primarily from countries in LAC. The observed types of migration included international (voluntary, forced, or humanitarian). Articles focused on measuring mental health (MH) and the access/use of healthcare services. Regarding MH, it was observed that the young migrant population exhibited worse indicators than the adult population, while both migrant and Chilean populations exhibited similar MH statistics, with socioeconomic level (SEL) being a significant determinant. Access to healthcare services has increased among the migrant population and is contingent upon SEL. Only two articles have addressed subjects related to reproductive health, with none discussing sexual health. Official reports focused on characterizing the population and their access to services (healthcare, education, housing, occupational situation), border mobility, poverty index, social perceptions, and inclusion. Most studies have utilized secondary data provided by official sources. Migration toward Chile primarily involves south-south migration, sociodemographic characterization, and issues accessing services, including healthcare. Results highlight a scarcity of studies collecting primary data, leading to a lack of relevant indicators for understanding aspects such as migration causes, attracting factors, migration trajectory, migration status, cross-cultural relationships, or sexual health.