LAUSR

Background Recruitment for research is usually expensive and time consuming. Facebook (FB) recruitment has become widely utilized in recent years. The main aim of this study was to assess FB as a recruitment tool in a study for Spanish- and English-speaking smokers. Additionally, the study set out to compare performance of ads by language (Spanish vs. English), location (U.S. vs. San Francisco) and content (self-efficacy ad vs. fear appeal ad). Methods Participants of a one-condition smoking cessation webapp study were recruited utilizing FB ads and posts through two phases: a recruitment-focused phase and an experimental phase comparing language, location and content. Results During the recruitment phase 581 participants in total (U.S. = 540, San Francisco = 41) provided consent. Of the U.S. participants 275 were Spanish-speakers and 265 English-speakers. The cost-per-consent was $25.81 for Spanish-speakers, and $15.49 for English-speakers. During the experimental phase U.S. users performed better (i.e. more clicks, engagement and social reach) than San Francisco users, Spanish-speakers engaged more than English-speakers, and the self-efficacy ad performed better than the fear appeal ad. Conclusions This study showed that although there were differences in cost-per-consent for Spanish- and English-speakers, recruitment of Spanish-speakers through Facebook is feasible. Furthermore, comparing performance of ads by location, language, and ad content may contribute to developing more efficient campaigns.