Abstract
The unit of intervention is a school drive, i.e., a stem cell registration event at a high school or vocational school. After a presentation by trained volunteers, students can register in the stem cell registry via a test kit (buccal swab) and by providing the required information needed upon registration (contact details). Directly after registration, the donor receives a confirmation email.
For the intervention, students are randomly allocated to treatment and control group schools (equal split). For the control group, the standard registration protocol at a regular school drive applies.
The treatment group receives the standard protocol with an additionally communicated exit option (opt-out) during the donor drive, informing them that they will have the option to opt out of the registry when receiving the confirmation email. The default communication in the confirmation email of the treatment group is to stay in the registry, but it will also contain a link to an exit landing page. By clicking on this link, treatment participants have the opportunity to actively exit the registry (opt-out).
To understand potential heterogeneity in responses to the intervention, we run a short digital follow-up survey with subjects from the control and treatment groups. The follow-up survey contains questions on subjects’ motivations to join the registry, economic and social preferences, personality traits, and informedness about the extraction methods. We also aim to survey individuals who choose not to register at on-site events, using equivalent items and questions to understand their reasons for not joining the registry.
Additionally, the survey will include questions on factors such as the role of peer comparisons in the decision to register. We will ask participants about the registration behavior of their peers (e.g., how many of their friends registered or did not register) and explore beliefs regarding their own and others’ actual availability for donation. If possible, we will incorporate incentivized measures to elicit beliefs about social norms related to peer pressure and availability, in order to classify types of individuals. Moreover, we plan to randomly vary the feedback about the impact of peer influence to examine how this information shapes participants’ responses about their own availability and willingness to donate. If possible, we will also include questions allowing us to analyze how additional factors would have influenced the likelihood of registration or the perceived trust in the organization.