Plans to promote participant retention and complete follow-up {18b}
To promote participant retention, participants can only receive reimbursement for their participation (either partial course credit or taking part in the lottery and having the opportunity to win an Amazon voucher) when they completed all three assessments of the study (pre-intervention, post-intervention, follow-up). To promote retention in the control group, the trial has a waiting list control condition, in which participants can download one of the two intervention apps after they completed the study.