This paper explores digital peer assessment in an interdisciplinary project Open Spaces, involving peer feedback with comparative judgement of students’ responses to an authentic real-life problem. Reporting from a case study where comparative judgement facilitated peer feedback undertaken an open-ended design scenario in primary STEM education. Students redesigned an open public space from a UN Agenda2030 perspective, including both theoretical and practical work. Primary students worked in groups of three or four and then they individually peer-assessed each other’s work via Adaptive Comparative Judgement (ACJ). Research design facilitating for several schools to be involved in peer-feedback activities, Hence, allowing students to view and provide feedback to a potentially larger and more varied set of examples, and through that learn from more than traditional face-to-face peer feedback through compiled feedback comments and self-reflection. Comparative judgement may facilitate for students to become owners of their own learning and learning resources to their peers -as both providers and receivers of feedback beyond traditional means. Confirming previous results on comparative judgement as particularly suitable for assessing open ended design scenarios, adding to the conversation on peer assessment. Hence, there is a great potential of embedding comparative judgement in STEM education to support learning, facilitating the double directed feedback process identified here but needs to be investigated further.