Celestina Heepen (ETH Zürich, Switzerland) will give this seminar, organized by the ELI-A department. 

Abstract 

Media reports and qualitative research regularly document precarious conditions (i.e., low wages and health risks). Yet their prevalence remains unclear due to limited quantitative data. 

Farm workers—especially seasonal migrants—are difficult to sample using standard methods due to absent registries and mobility. We address this gap by testing respondent-driven sampling (RDS), a health research approach for hard-to-reach populations. 

Its intuition is similar to snowball sampling (where respondents recruit subsequent respondents), but, if certain assumptions are met, yielding more representative data. Though promising for addressing farm worker data gaps, the tool has not been tested for this population. 

We focus on Swiss horticulture, where data collection is particularly difficult, due to linguistic diversity among both workers and farmers, in addition to the common problem of missing official registries and strict data protection laws. To manage language diversity (ca. 15 languages), we use web-based RDS. Testing RDS, we first recruited workers through farm employers who forwarded the survey, using contacts from the Federal Office of Agriculture. This yielded few responses, despite incentives, reflecting farmers’ reluctance to forward the survey and migrants' hesitation about an employer-distributed study on working conditions. 

We implemented stepwise modifications, like using worker-organisation as starting points (aka seeds), rather than farmers. We find that reaching representative samples of geographically dispersed, linguistically diverse, and poorly organised, vulnerable populations cannot be fully addressed by web-based RDS. 

Thus, collecting farm worker data in higher-income countries remains an important challenge. We argue that the most effective approach is for governments to extend labour-force surveys to seasonal migrant workers, leveraging their access to contact details. More data and research are needed, given the increasing policy attention to social sustainability in European farm, labour and corporate due diligence policy, where seasonal migrant workers are currently typically not captured in policy evaluations.