This methodological research design has been developed within the framework of work package 5 of the European project "Assessment of Transversal Skills in STEM (ATS-STEM) and has been carried out by the educational technology group of the University of Santiago de Compostela (http://tecnoeduc.es) and are available from the project website: https://www.atsstem.eu/resources/ It contains the complete methodological design and all the instruments necessary to implement the evaluative research design created within the framework of work package 5 of the project. the purpose of this design is to ensure the elaboration of a scientific research report documenting the results obtained in the pilot conducted in schools in 7 European countries. this instrument was developed so that all participating researchers in the 7 countries would share the same common framework and tools, thus ensuring rigor and homogeneity in the quantitative and qualitative data collection processes and in the elaboration of the national research reports. this publication is complemented by the transnational research report carried out within the framework of the project, which will also be published.