Study design and study population
RECRUITMENT
This study reports the intervention outcome effectiveness of a
12-month cluster-randomized waiting-list controlled trial in Swedish
public schools (comprising elementary, middle and high school levels).
In Sweden, education is compulsory for 10 years starting at the age of
6 and continuing until grade 9 (15–16 years). The participating
schools were randomized based on municipality and school size
stratification into either multifaceted group or discrete group in a
1:1 ratio. The multifaceted strategy included an educational meeting,
local implementation teams, workshops, and an iterative and evaluative
strategy. The discrete strategy only included the educational meeting.
After 12 months, the schools in the discrete group received the
remaining strategies. The trial was registered on ClinicalTrials.gov
(NCT03322839), assigned date: August 2017) and approved by the Ethical
Committee of Stockholm (2017/984-31/5) (The initial recruitment was at municipality level and followed a
two-step process. First, advertisements were disseminated through
newsletters, such as the Swedish Association of School Principals and
Directors of Education and the Swedish Union of Teachers. Two
municipalities showed an interest and agreed to participate. In the
second step, the research team presented the study to principals in
these two municipalities. One municipality had seven public schools,
whereas the other had thirteen. The Swedish school system is
tax-financed, and the municipality allocates resources to the schools
(SFS:2010:800).Several strategies were used to recruit participants at the school
level. The research team visited each school to introduce the study.
During this visit, the school personnel also had the opportunity to
ask questions regarding the study. Those individuals absent at the
presentation received a link to a recorded presentation. All
participants received an information letter, including the study’s
purpose, the research approach, voluntary participation, and
information about the data collection process. Furthermore,
individuals who agreed to participate received an informed consent
form, which was completed and returned to the research team. All
personnel employed by the school management were eligible for
participation. A total of 698 individuals agreed to participate and
answered the baseline questionnaire, which gives a response rate of
83.1%. As the guideline recommendations targeted the organizational
level, an open cohort was employed in the current study, which means
that participants were able to join the study at 6 and 12 months.