Educational institutions are confronted with increasing pressure from authorities and governments to justify their spending of public means. This, in turn, has led to increased internal use of the huge amounts of data in information systems on results, careers, absence, etc. Experience with a data analysis product that is actively used in 20+ schools (secondary education) indicates that visual presentation and user interaction are crucial to have analyses of large datasets lead to real improvement. Intricate and finely-tuned interaction between methods from the field of data mining and these interactive techniques may further aid schools.