Implementation measure
A web-based survey was delivered to school principals about the implementation of the intervention components approximately four months (November) after baseline (August). Based on these responses, a variable was derived about the implementation level. Categorizations of schools were divided into (1) implementation of both school- and class-level intervention components (intervention delivered in full), (2) or only some class-level components or withdrawal of components during the evaluation period (partial intervention), and (3) control schools.