The school-principal forms an implementation team that is responsible for implementing the guideline within their school. The team members (n=4-5) reflect on the implementation progress, make, and refine plans according to Plan-Do-Study-Act, share lessons learned and support each other.

The investigators will hold 5 workshops. Workshops will include providing in-depth knowledge and skills on the guideline recommendations. During each workshop one of the guideline recommendations will be presented and discussed.

Moreover, the concept of Plan-Do-Study-Act will be introduced and how it can be used to implement the guideline recommendation(s). During each workshop, the implementation team will share with the group their developed PLAN and barriers and facilitators that have influenced the execution of the PLAN.

The implementation team will implement the guideline in a cyclical manner by using Plan-Do-Study-Act. First a Plan is specified during the workshop by using SMART-goals, next the change is carried out between workshops (Do), the implementation team analyses whether it went well and what needs to be improved (Study), changes are made (Act) and finally the next cycle is planned.

Each municipality assigns one or more internal facilitators, for example HR-strategist. The internal facilitator will meet their local implementation teams during the educational meeting and workshops. Further meeting can be scheduled based on the needs of each implementation team. The internal facilitator will create a supportive environment within which knowledge is exchanged, barriers to implementation identified, and processes or solutions to overcome those barriers developed, applied, and refined. Moreover, the internal facilitator will establish ongoing audit and feedback processes.

Change from baseline in psychosocial safety climate during 12-, and 24-months follow-up. Psychosocial safety climate is assessed with PSC-4, which is a short questionnaire with 4 items measuring the Psychosocial Safety Climate at work (Berthelsen & Muhonen, 2017)

Change from baseline in organisational readiness to implement the guideline during 12-, and 24-months follow-up. Organisational readiness to implement will be assessed with the Leader Readiness to Implement Tool (LRIT) developed and validated by Cook et al. manuscript submitted. With the tool a total readiness index will be calculated, but also a change efficacy score and a change commitment score indicating the confidence and commitment to implement the guideline within the organisation (school).

Change from baseline in implementation leadership during 12- and 24-months follow-up. Implementation leadership will be assessed with items from the S-ILS (Aarons, Ehrhart, & Farahnak, 2014; Lyon et al., 2018). The S-ILS assesses the degree to which a leader is Proactive, Knowledgeable, Supportive, and Perseverant in implementing evidence-based practice (the guideline). Scores for the subscales will be calculated and a total score for the S-ILS is calculated by taking a mean of the scale scores.

Change in skills during 12-months. Skills is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for skills.

Change in social/professional role and identity during 12-months. Social/professional role and identity is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for social/professional role and identity.

Change in beliefs about capabilities during 12-months. Beliefs about capabilities is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for beliefs about capabilities.

Change in beliefs about consequences during 12-months. Beliefs about consequences is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for beliefs about consequences.

Change in reinforcement during 12-months. Reinforcement is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for reinforcement.

Change in intention during 12-months. Intention is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for intention.

Change in goals during 12-months. Goals is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for goals.

Change in environmental context and resources during 12-months. Environmental context and resources is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for environmental context and resources.

Change in social influences during 12-months. Social influences is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for social influences.

Change in behavioral regulation during 12-months. Behavioural regulation is assessed with items from the Theoretical Domains Framework (TDF)-questionnaire (Huijg et al., 2014). The TDF-questionnaire assesses factors influencing the implementation of the guideline. In the project the questionnaire will be used to asses potential mediators that influence guideline implementation. A sum-score will be calculated for behavioural regulation.