This document presents the results of the Bilbao pilot , a community intervention developed in Suba-Bilbao by the Corona Foundation and the Social Group Foundation, which aimed to strengthen trust, collaboration and citizen participation through waste separation at the source , using behavioral science tools .

The project began with a central challenge: addressing low levels of trust among neighbors, limited community collaboration, and persistent problems with waste management—factors that hindered the possibility of building sustainable collective solutions. In response to this situation, the pilot project designed and implemented a portfolio of interventions that combined educational, artistic, communicative, and public engagement activities, all developed through direct dialogue with the community.

Throughout the document, the methodological process is described , from the diagnosis of the context and the identification of key behaviors, to the design of solutions, their implementation in the field, and the subsequent pre- and post-intervention monitoring and evaluation , with treatment and control blocks. This approach made it possible not only to measure changes in waste disposal practices, but also to analyze broader transformations in interpersonal trust, perception of social norms, collaboration, and willingness to participate .

The results show significant progress : substantial increases in overall trust, greater trust among neighbors and toward waste pickers, increased community participation, and strengthened environmental practices, including a jump from 0 to 100 kg of recycling in the targeted blocks. Beyond the data, the pilot program yielded key lessons on the importance of community-based work, the role of local leaders, the value of children as drivers of mobilization, and the need to design flexible and adaptive strategies.

This document aims to serve as a learning and reflection resource for stakeholders working in trust, collaboration, community management, and urban sustainability, and offers concrete guidance for scaling up and adapting these types of interventions to other territories. Above all, it is an invitation to explore how behavioral changes, when built collectively, can become a powerful lever for transforming community life.