Procedure
RECRUITMENT
The ROs in each country followed a standard operating procedure established by the MENTUPP consortium in the recruitment and implementation of the intervention. The ROs were a local steering committee, comprised of key stakeholders of the three sectors, experts in workplace mental health promotion, and academia. An invitation letter to participate in the pilot was sent to SMEs by the ROs, along with an information leaflet detailing basic information about the pilot study and the MENTUPP Hub. An initial meeting with the SME director or a member of the management was set up to discuss the details of participation in the MENTUPP pilot study. ROs assigned to each one of the recruited SMEs established a pilot planning group including at least one employee and one member of the management and then developed an action plan to address psychosocial work environment factors (Arensman et al. Introductory sessions were organised with employees and employers approximately two weeks prior to the implementation. During the introductory sessions, the ROs explained the purpose and nature of the study including information on evaluation measures emphasizing that participation is voluntary and that anyone could withdraw at any time. It was noted that employers did not have access to the surveys completed by the employees and that participation would not impact their circumstances of employment in any way, neither positively nor negatively.Once the participants expressed their interest in the study, they were provided with access to a link leading to the pre-intervention surveys (baseline assessment). First, participants were asked to give informed consent and then they could complete the baseline assessment. To assure participants’ anonymity, a subject-generated identification code (ID-code) was used. The effective use of such an ID-code, allows successful matching of participants across time, depending on the variables that are chosen to generate the ID-code (Yurek et al. After completing the survey, participants were required to register with the Hub, creating an account to access the materials. SMEs were requested to allow their employees to engage with the Hub during working hours over a six-month intervention period. The time investment to engage with the materials was estimated at eight hours in total which corresponded to an average time use of twenty minutes a week. Following the six-month intervention period, participants were asked to complete the post-intervention surveys (follow-up assessment).The MENTUPP Hub was opened in March 2021 and remained accessible for six months. Baseline data were collected in March and April 2021 and follow-up data collection was completed in December 2021. Qualtrics 