Innovative Strategies for Remotely Sampling Hard-to-Reach Populations: Assessing Phone Versus Internet Respondent-Driven Sampling Approaches Among Venezuelan Refugees and Migrants in Colombia.

It is challenging to quantitatively measure the health vulnerability and risk factors of refugees and migrants residing outside of formal settlement settings. For hard-to-reach populations without available sampling frames, researchers have increasingly turned to novel sampling and statistical methods, like respondent-driven sampling (RDS). "Standard" RDS is typically conducted face-to-face at fixed sites.

Assessing the impact of the COVID-19 pandemic among Venezuelan refugees and migrants in Colombia using respondent-driven sampling (RDS).

Objectives: To determine factors associated with adherence to COVID-19 mitigation measures, related symptoms and testing, as well as pandemic-related income loss among Venezuelan refugee and migrant adults in urban and border areas of Colombia.

Design: Phone-based respondent-driven sampling SETTING: Bogotá and Norte de Santander, Colombia.

Participants: 605 adult Venezuelan refugees and migrants residing in Bogotá (n=305) and Norte de Santander (n=300), who arrived in Colombia after 2014 and completed the survey in August and September 2020.