Teaching staff are expected to be able to use results from comprehensive student achieve-ment tests to improve their instruction. For these data-driven decision-making processes, skills that could be denoted as data literacy are required. Research has shown, however, that in some cases these competencies are not sufficiently pronounced and that feedback is often difficult to understand. Furthermore, the research demonstrated that it is necessary to in-crease the comprehensibility of feedback by using data visualizations. Regional state insti-tutes for education tasked with providing feedback supported teaching staff by offering fur-ther training and handouts on how to use external achievement test results. The matter of increasing the comprehensibility of feedback remains unaddressed. This gap in the research will be taken up in this thesis, which uses the example of comparative achievement tests to approach the question of whether the comprehensibility of achievement-test feedback could be increased by using a feedback system with interactive information visualizations. As part of a study with a cross-sectional design, twenty primary school teachers compared a familiar paper-based feedback for achievement-test results with a new, interactive feedback system. First, the teachers participating in the study assessed the perceived time required to answer the questions asked about the test results. Secondly, the teachers assessed how useful the feedback formats were for answering the questions. The results show that, on average, the questions asked about the data could be answered significantly more quickly using the interactive information visualizations. Furthermore, interactive information visualizations are assessed as being significantly more useful on average. Matrix visualizations were prov-en to have particularly positive effects. For the co-variables only one significant effect was perceived: Teachers with a high level of data literacy assessed the interactive feedback sys-tem as being faster. Moreover, the teachers gave statements regarding requirements for an interactive feedback system and their attitudes and experiences in working with achievement tests. The findings of this study indicate that feedback systems with a user- and demand-oriented graphic layout are becoming more important
