A survey that should prove the effectivity of SRL has been carried out at different types of school - Mittelschule, Realschule, Wirtschaftsschule, Fachoberschule, Gymnasium. 70 classes, 50 teachers and 1863 students took part in that study.
Through the LTE-Network it was possible that another 15 European countries with more than 300 teachers took part in that study. All in all almost 10 000 students - in Germany and the participating European countries - work with SRL. These results of that survey had been published in two volumes in 2019.