The goal of this study is to evaluate whether a digital, game-based social-emotional education intervention (SEL4@ll) can improve socio-emotional competencies, well-being, and inclusion in primary and secondary school students aged 10-16 across four European countries. The main questions it aims to answer are:

• Does participating in the SEL4@ll serious game increase students' socio-emotional competencies, such as self-awareness, empathy, and decision-making?
• Does the program enhance students' sense of well-being and social inclusion within the classroom environment?

Researchers will compare outcomes between students who participate in the SEL4@ll intervention and those in the control group who follow standard curricular activities to see if the game-based program leads to significant improvements.

Participants will:

• Play a serious game focused on five themed "portals" that develop emotional intelligence, leadership, gratitude, resilience, and justice.
• Complete questionnaires at three different time points (pre-, post-, and follow-up) to assess changes in competencies.
• Take part in focus groups (students) and provide implementation feedback (teachers).
• Engage in teacher-led activities and worksheets designed to support reflection and integration of SEL4@ll content.

SEL4@ll is an EU-funded, cross-national intervention designed to promote social-emotional learning (SEL) among primary and secondary school children using a serious game supported by pedagogical resources. The intervention aligns with the Collaborative for Academic, Social, and Emotional Learning (CASEL) framework and draws on evidence-based models of SEL, life skills development, character education, and positive youth development.

The serious game is the centerpiece of the intervention and is structured around five narrative "gates or portals," each of which targets three interrelated competencies:

Gate of Self: sense of meaning, resilience, leadership

Gate of Emotion: emotional intelligence, empathy, compassion

Gate of People: communication, gratitude, positive influence

Gate of Knowledge: motivation, growth mindset, critical thinking

Final Mission: equality, responsibility, justice

The game presents students as protagonists navigating magical environments to overcome a symbolic "dark force" by mastering SEL competencies, represented as branches of a "skill tree." The game is hosted online, accessible through a browser, and available in English, Spanish, Italian, German, and Finnish.

To facilitate educational integration, SEL4@ll provides a digital teacher handbook and didactic materials-including lesson plans and reflection worksheets-that help structure learning around the game content. Teachers play a vital role by guiding discussions and activities before and after gameplay.

The evaluation strategy includes both quantitative and qualitative components and follows a co-creation approach:

A three-wave design assesses students' development over time (pre-test, post-test, and delayed follow-up).

Quantitative measures include validated self-report questionnaires focused on SEL competencies, well-being, and perceived social inclusion.

Qualitative data are gathered through student focus groups and teacher interviews to explore experiences, perceptions, and implementation barriers.

Feedback from critical friends and stakeholders is used to iteratively refine the program materials and processes.

This study is conducted simultaneously in Germany, Spain, Italy, and Finland, allowing for a robust cross-cultural analysis of the intervention's effectiveness. Data will be analyzed both within and across countries to identify universal impacts and culturally specific outcomes, thereby informing future adaptation and scalability of the SEL4@ll model in broader European educational contexts.

This study is part of the Erasmus+ project "Promoting well-being among European adolescents: An inclusive and digital programme to strengthen socio-emotional competencies - SEL4@ll" and aims to contribute to evidence-based innovation in the transition form primary to secondary education by leveraging digital tools and inclusive pedagogy.

Inclusion Criteria

Participants must meet all of the following criteria to be included in the study:

• Be within the target age range (typically 10-16 years old, corresponding to 5th-6th grade of primary or 1st-4th year of secondary education).
• Have written informed consent provided by a parent or legal guardian.
• Complete all three measurement points (pre-test, post-test, and follow-up assessments).
• Attend school regularly (i.e., not chronically absent).

Exclusion Criteria

Participants will be excluded from the study if they:

• Do not obtain parental/legal guardian consent.
• Have significant cognitive, developmental, or language impairments that prevent them from understanding or completing the intervention or assessment tools.
• Are absent for a prolonged period during the implementation phase (e.g., due to illness, transfer, or other reasons).
• Participate in another intervention targeting similar outcomes during the study period, which may confound results.