2.2. The HHS Intervention
SECONDARY
The overall aim of the HHS Study was to promote well-being (the primary outcome) among first-year high school students in Denmark. We used the Intervention Mapping protocol [The HHS intervention consisted of four main intervention components which combined environmental and educational intervention strategies and were designed to change the important and modifiable determinants of the five secondary outcomes: (1) structural policies and initiatives at the school level, (2) a teaching material, (3) a peer-led innovation workshop and derived activities, and (4) a smartphone app. The intervention was implemented among first-year high school students in the school year 2016/17 and lasted for nine months (August 2016–May 2017). The intervention components are described below and presented in 