This chapter will describe a project that aims to provide teachers and students with necessary and efficient digital assessment approaches for the development of students’ transversal skills in STEM education. These approaches were developed, implemented, and evaluated through large-scale classroom piloting, leading to policy recommendations at national and European level for the further transformation of education. This international project included partners from Austria, Belgium, Cyprus, Finland, Ireland, Slovenia, Spain, and Sweden and was co-funded by partners and the European Commission under its Erasmus+ KA3 Policy and Experimentation initiatives. The aim of this innovative policy experimentation project was twofold. On the one hand, to “know and explain” the process of implementing the ATS STEM program and, on the other hand, to “understand” how it works in different contexts (schools, classrooms, countries) and thus make suggestions for improvement. This chapter will attempt to provide an overview of the commonalities and differences among the national standards in the countries involved in the ATS STEM project and compare them to the context of the Standards for Technological and Engineering Literacy: Defining the Role of Technology and Engineering in STEM Education (STEL).