Received: 11 April 2019
Accepted: 13 February 2020
First Online: 12 March 2020
Ethics approval and consent to participate
: Ethical approval by a research ethics committee was not required because this study was not covered by The Medical Research Involving Human Subjects Act (The Hague: Ministry of Health, Welfare and Sports: 1998). Verbal informed consent was obtained from study participants. This procedure for verbal consent was chosen because in an early stage of the study all participants together were informed about the aim, the organization, the procedures and the ethical requirements of the study. Because ethical approval by an ethics committee was not required, no ethics committee was involved by the verbal informed consent procedure. All participants accepted verbal consent and voluntary participated in this study that should contribute to improve supervision.
: Not applicable.
: The authors declare that they have no competing interests.