In this article we explore what data-based decision making use looks like in schools in five different countries (United Kingdom, Germany, Poland, Lithuania and the Netherlands). We explore for what purposes data are used in these countries and what the enablers and barriers to data use are. The case study results show that schools in all five countries use data for school development, accountability, and instructional improvement. Also, the schools in the five countries struggle with the same type of problems: e.g. lack of access to high quality data, lack of professional development in using data, and a lack of collaboration around the use of data. Finally, we discuss how some enablers can turn into barriers for effective data use.