<![CDATA[This study aimed to design and refine a community-based professional learning system through the Teacher Working Group (Kelompok Kerja Guru/KKG) to support contextual science teaching in elementary schools. The study employed a qualitative Design-Based Research (DBR) approach involving eight fourth- and fifth-grade teachers from SDS Al-Fitriah and SDS Yapsi in Medan Johor District, Medan City. The research was conducted through iterative DBR phases consisting of (1) analysis of teachers’ professional learning needs and existing KKG practices, (2) design of an initial KKG prototype based on contextual science learning principles, (3) implementation and formative evaluation through classroom observations, interviews, document analysis, and reflective discussions, and (4) revision of the prototype based on empirical findings and expert feedback. The iterative cycles resulted in a refined KKG model that met the criteria of validity, practicality, and effectiveness. Validity was confirmed through expert evaluations indicating that the prototype possessed high content and construct validity. Practicality was demonstrated by implementation fidelity exceeding 85% and positive teacher perceptions regarding the relevance and usefulness of KKG activities. The study contributes a validated prototype for sustainable teacher professional learning and extends DBR research by emphasizing the collaborative design process within KKG as a mechanism for strengthening contextual science literacy in elementary education, rather than focusing solely on student learning outcomes.]]>
