Compliance
Compliance was defined as the site or trial staff giving or sending the participants their trial voucher at the time they were randomised to receive it. All participants in the conditional incentive group received their vouchers. Within the non-conditional group, there were 5 participants who did not receive the vouchers as they should have done. This was due to site non-compliance and non-response to the trial team who were trying to restock their vouchers. The site was re-trained and the issue did not occur again.