During this study ENISA gathered and analysed a large set of over 200 exercises. In addition to the exercise dataset, ENISA analysed specialised literature such as after-action reports and previous studies that have contributed to the analysis. This report includes a model for describing and reporting on such exercises. The study is a step forward towards better resource for planning and collaboration between nations and agencies interested in cybersecurity exercises. The findings show a continuous and accelerated increase in the total amount of exercises held after 2012, as well as an increase in the number of cooperative exercises involving private and public actors. This indicates that it is not just a matter of public agencies running more exercises, but also of more actors benefiting from these exercises.