Methodological Openness and Social Sustainability in Secondary Education: Sociometric and Perceptual Evidence from Project-Based Learning

This study examines how methodological openness is associated with the social sustainability of learning in secondary education. A comparative, non-experimental, exploratory mixed-methods study was conducted with two secondary school classroom groups that completed the same technological task—the construction of a functional drawbridge—through two project-based learning configurations: a highly structured Guided Project and a more open STEM-PBL configuration. Data were collected through a sociometric questionnaire, a perceived group functioning scale, and open-ended student responses, yielding structural, perceptual, and qualitative evidence on classroom interaction. The results indicate that the open STEM-PBL configuration appeared to be associated with a more cohesive and integrated relational structure, reflected in higher reciprocity, lower isolation, and more distributed peer connections. Conversely, the more structured approach appeared to be associated with more positive and stable student perceptions of cooperative work, particularly in relation to responsibility, participation, peer support, and organizational stability. The central finding is a dissociation between the structural pattern of peer choices and students’ perceived experience of cooperative group functioning. These exploratory findings suggest that socially sustainable learning environments depend not simply on expanding student autonomy, but on balancing openness, structure, and teacher mediation in ways that support relational inclusion, equitable participation, and group cohesion.