This report (Report #5) was written as part of a research project titled, Assessment of Transversal Skills in STEM (ATS STEM). The project is funded by Erasmus+ (Call reference: EACEA/28/2017 - European policy experimentations in the fields of Education and Training, and Youth led by high-level public authorities). The development of the ideas, concepts and understandings presented in this final report is visually synthesised in Towards the ATS STEM Conceptual Framework. Towards the ATS STEM Conceptual Framework aims to inform the classroom practices of integrated STEM education topics and their assessment. Educators can benefit from such a conceptual framework encapsulating the key ideas from the literature and that helps to inform their understanding and subsequent classroom practice.