Exploring Different Sampling Strategies: A Description of Our Success in Reaching Hard-to-Reach Turkish and Moroccan...

In the Netherlands, since 1996, there is a national cervical cancer (CC) screening programme in place for women aged 30-60 years. The participation of Turkish- and Moroccan-Dutch women is very low. To facilitate their informed decision-making, we developed a culturally sensitive educational video, and evaluated it through a questionnaire study. Since we used multiple strategies for the recruitment of respondents, we aimed (1) to explore which sampling strategy resulted in which type of respondents, (2) to investigate which sampling strategy and individual characteristics were associated with successful recruitment of other respondents, and (3) to examine similarity between those recruited via respondent-driven sampling (RDS).

Six sampling strategies were used and compared to explore their recruitment success: (1) RDS (i.e. peer-to-peer recruitment), (2) public and private women's Facebook groups, (3) Instagram, (4) researchers' network, (5) offline organizations (e.g., community centres and mosques), and (6) other channels (e.g. flyers, infographics, and information meetings). To do this, χ² tests, a multivariate logistic regression, and intra class correlations (ICCs) were performed.

Overall, 782 Moroccan- and 696 Turkish-Dutch respondents were included in the analysis. Almost 40% filled out the questionnaire via RDS. RDS yields more often older, lower educated, and first-generation immigrant women than average. Respondents recruited via RDS have more often low CC screening knowledge and make more often uninformed CC screening decisions than average. Social media channels, however, yielded more younger, highly educated, and second-generation immigrant women than average. Sociodemographic characteristics and attitudes towards CC screening varied more strongly within than between network trees. The probability that paired respondents within a network tree had similar characteristics varied strongly depending on the characteristic.

By using RDS and asking respondents to recruit peers, the more hard-to-reach individuals (i.e. older, lower educated, and first-generation immigrants) were reached. By using social media channels, younger, highly educated, and second-generation individuals can be recruited. RDS yielded more often women with low CC screening knowledge and women making uninformed CC screening decisions. To reach the individuals in need of tailored information or an intervention conform their needs, we recommend to use RDS as an intervention delivery strategy.

Following RDS, we involved Moroccan- and Turkish-Dutch women in recruiting other Moroccan- and Turkish-Dutch women. Through this recruitment, women were able to fill out our questionnaire, and watch our culturally sensitive educational video to improve their informed decision-making in regard to the CC screening programme.