Abstract
This study examines how cross-subject integration in STEM education can be embedded within formal curriculum structures through institutional design rather than individual teacher initiative. The research was conducted at a STEM-specialist secondary school in Astana, Kazakhstan, where informatics functions as a coordinating subject across science and humanities disciplines. The study analyses two dimensions of curriculum organisation: (1) the vertical progression of the informatics curriculum across Grades 6–10, from digital literacy and data handling to programming and independent project work; and (2) a horizontal coordination mechanism in which informatics and subject teachers design shared learning tasks and independently assess different dimensions of the same student products. Data include curriculum documents, assessment rubrics, student project work ( n = 36 students, comprising three complete project groups from the chemistry integration cycle), and teacher perspectives collected through informal conversational exchanges. Findings document how co-assessment structures differentiated disciplinary feedback from two independent knowledge positions within a single task, and how teachers perceived this structure as making disciplinary expectations more explicit in student preparation. The study introduces the concept of an interdisciplinary assessment ecology as a distributed evaluation structure in which subject specialists assess distinct dimensions of shared student artefacts. The results suggest that such integration can be implemented through formal planning routines embedded in existing curriculum structures without additional curriculum time for students or external funding, though it does require coordinated teacher time for quarterly cross-departmental planning sessions.