Improvement of (didactical) assessment by improvement of problems: An attempt with respect to percentage

In recent attempts to reform assessment much attention is devoted to the formats of assessment and organizational aspects. Without good problems, however, it is impossible to improve assessment. This article focuses on the role of problems in the development of better assessment. An example of an attempt is given with respect to some key concepts and abilities on percentage. A series of problems for assessing these has been developed inspired by the ideas of Realistic Mathematics Education. The guiding principles were that problems should be meaningful and informative. The problems, which are rather different from the traditional kind have been tried out in two American grade 7 classes. The problems reveal a lot about the different levels of understanding of students. As such they can facilitate instructional decision making. Nevertheless it is clear that this is not the final stage of the search for better assessment problems. As a start to further developmental research, some recommendations will be given for the improvement of the problems.