In summary, over the course of the first year of the project 4016 invitations were sent, with an overall participation rate of 68% (N = 2715); 95% of whom picked up their payments. Of the 2574 participants who picked up their survey payments, 97% also chose to participate in the DNA part of the study (N = 2506). Each e-mail invitation contained the option to withdraw from the study by clicking on a link. Only 17 students (<1%) withdrew from the project. Figure 1 provides an overview of participation rates.
