BACKGROUND:
Co-production is increasingly promoted as a strategy for developing context-specific and sustainable interventions to address complex environmental and public-health challenges. However, there is limited empirical evidence on the effectiveness of co-production processes in generating legitimacy and strengthening implementation readiness, particularly in low-resource settings. This study evaluates the co-production process underpinning the development of a multisectoral community-led plastic waste management intervention in rural Indonesia.

METHODS:
Upon completion of the co-production of the multisectoral intervention, we conducted a qualitative process evaluation across six villages in Malang District, Indonesia. Guided by the Medical Research Council framework for complex interventions and the Research Quality Plus for Co-Production (RQ+4 Co-Pro) framework, we examined contextual factors and core quality dimensions of co-production, including relevance, rigour, legitimacy, inclusivity, and positioning for use. Data were collected through focus group discussions, key informant interviews, post-workshop surveys, and researcher field notes involving community members, waste practitioners, and local government actors. Transcripts were analysed thematically using NVivo.

RESULTS:
In total, 33 participants engaged in co-production evaluation. Six interrelated themes characterised the co-production process: (1) access to contextually relevant knowledge and learning resources; (2) iterative learning and feedback as drivers of collective problem-solving; (3) strengthened capacities for collaborative knowledge generation; (4) inclusive and well-facilitated participatory design; (5) trust-building and mutual respect across stakeholder groups; and (6) locally grounded and actionable intervention pathways. Participants reported that structured, multi-phased workshops and culturally sensitive facilitation enabled equitable participation, reduced power asymmetries, and integrated local knowledge with technical expertise. The co-production process enhanced ownership, social legitimacy, and confidence in the feasibility of the co-produced intervention prior to implementation.

CONCLUSIONS:
This study adds to the scarce evidence base that structured, inclusive, and adaptive co-production processes can strengthen research quality, community capacity, and intervention readiness through developing locally relevant and actionable solutions to complex environmental health challenges.