Multinational dataset of secondary school students in Belgium (Flanders), Czechia, Denmark, Germany and the United Kingdom (pre-test and post-test). Data access: An embargo period of 24 months after the end of the project is foreseen for this dataset (01/04/28). This is to allow the project team sufficient time to write and publish research papers based on this data as explained in Data Management Plan. After this period, interested researchers should contact authors and community manager (gepicproject@gmail.com) to submit an application to access the dataset.