Assessing group work formatively in higher education poses a significant challenge. The complexity of evaluating individual contributions is compounded by the lack of efficient and effective methods for tracking, analysing and assessing individual engagement and contributions, which can impede timely feedback and the development of group work skills. This paper contributes to the growing body of research on collaboration analytics, which focuses on learning analytics (LA) in collaborative settings, and formative assessment while providing practical guidance for educators seeking to enhance formative assessment practices. The potential enhancement lies at the intersection between analytics technology and assessment design. In this paper, we present a conceptual framework that can harness multimodal data collection as well as LA to formatively assess and provide feedback on individual engagement and contributions to group work across physical and digital spaces. Drawing on research that considers design for learning, conjecture mapping, assessment design, multimodal LA and feedback, we outline a structured approach to developing formative assessment of group work skills in collaborative projects and higher education contexts.