The target population included all students in the 4th year of the HarmoS curriculum who were enrolled in a public or private school, followed a Swiss national curriculum, and were taught in one of the three languages: German, French, or Italian. Nationwide, the target population comprised approximately 88,000 students from nearly 5,000 schools. Special education schools were omitted due to methodological constraints. Exclusion criteria for students were limited to cognitive or functional impairments or insufficient proficiency in the language of instruction, while academic underperformance or disciplinary issues did not constitute grounds for exclusion.
