Participants
RECRUITMENT
Elementary schools within four school districts in the Lower Mainland of British Columbia, Canada were invited to participate in this project. Recruitment for Cohort 1 took place between September and December 2018. All principals at eligible schools (public schools within the four districts for which district approval was obtained) were contacted by email for initial interest in the study. Following an expression of interest from a principal, a meeting with the principal and eligible teachers was conducted. After the meeting, schools determined whether they wanted to participate, and which classes would be involved. Schools were asked to provide at least one class of older students (Grade 6/7; ages 12–13), as well as up to three classes of younger students (ages 8–10). Grade 7 represents the last year of elementary school in the target school districts. Split grade classes are common thus the class of older students could have been all Grade 7 students or both Grade 6 and 7 students. For younger students, classes were also split, but only Grade 3 and 4 students took part in the study (enrolled in all Grade 4, 3/4 or 4/5 split classes). The only exclusion criterion at the student level was a basic working knowledge of English. Active parental consent, as well as child assent, were obtained before enrollment in the study.