Table 2 Overview of  the measurements of the different process evaluation concepts

1a) Reach (participation rate) Description of who participated and who did not

Schools - describe by type and composition (gender, SES, ethnicity)

Adolescents - gender/age/school type/SES

Drop-outs - Description of those participating and those not

2a) Dose delivered (completeness) Implementation of all components

Before the start of the intervention, a presentation will be given to the involved teachers and principals to inform them about the intervention and the weekly process evaluation moments.

A weekly process evaluation moment will be conducted in the classroom by the teachers or researchers depending on schools’ and teachers’ preference.

During this weekly moment, a classical discussion will be held to evaluate the previous game week, to ask about possible problems, to introduce next week’s week story/challenge and to highlight the importance of continuing with the intervention/game. Weekly logs will be held to capture this process.

2b) Dose received (exposure) Participants engagement, interaction, initial and/or continued use

Dose received (exposure) will be measured via two ways: 1) the core game module of the game experience questionnaire that will be included in the post-test questionnaire, and 2) the in-game logs.

2c) Dose received (satisfaction) Satisfaction with intervention

Dose received (satisfaction) will also be measured via the game experience questionnaire.

3) Fidelity Implemented as planned.

Researcher weekly logs - summary of comments/open ended questions on weekly logs

3) Context Physical/social/political contextual factors that might influence implementation/reach

School management questionnaire to describe differences in school systems/organizations and priority of nutrition

Teacher post intervention questionnaire, Principle post-test, and question in adolescent posttest questionnaire on school related factors likely to influence implementation/contamination