Due to global water consumption and an intensification of the resulting consequences there is a need for education regarding sustainable water consumption. Regarding Education for Sustainable Development, the ongoing water use of the industrialized countries needs to be discussed in the classrooms. Therefore, the aim of this paper is to present and use a questionnaire for the survey of students’ conceptions of sustainable water use. In order to enable educational reconstruction, conceptions about sustainable development and virtual water have been surveyed. The latter aspect of conceptions has been divided into different spatial conceptions and knowledge about water intense products. It has been shown, that the students’ conceptions are similar to scientific concepts, but learners also have their own conceptions. According to these findings conclusions for improved learning and teaching on sustainable water consumption are derived, to achieve more comprehensive students’ conceptions.

Systems thinking is one of the skills necessary for sustainable behavior, especially regarding sustainable consumption. Students are faced with complexity and uncertainty while taking part in it and other daily life aspects. There is a need to foster their competence in this field. From a classroom point of view, the mystery method is an example for implementing education for sustainable consumption and working with complex and uncertain content. With the mystery method students construct an influence diagram, which consists of concepts and requires several skills, especially in decision-making. Using these diagrams as a form of assessment is desirable but also very difficult, because of the mentioned complexity and uncertainty that is part of the task itself. The study presented here tackles this problem by creating an expert based reference diagram that has been constructed with the help of educational data mining. The result shows that it is possible to derive such a reference even if parts remain ambiguous due to the inherent complexity. The reference may now be used to assess students’ systems thinking abilities, which will be undertaken in future research. Beside this, the reference can be used as a reflective tool in lessons, so students can compare their own content knowledge and discuss differences to the experts’ reference.

Influence diagrams, derived from the mystery method as its learning output, represent an externalization of systems thinking and are, therefore, valid to research; so far they have not been conceptualized in the research literature for teaching systems thinking in education for sustainable development. In this study, 31 of those diagrams are confronted with (1) three different expert references, in (2) two different ways, by (3) three different scoring systems to determine which evaluation option is both valid and easy to implement. As a benchmark, the diagrams’ diameters are used, which allows statements about the quality of the maps/diagrams in general. The results show that, depending on the combination of variables that play a role in the evaluation (1, 2, 3), the quality of the influence diagram becomes measurable. However, strong differences appear in the various evaluation schemes, which can be explained by each variable’s peculiarities. Overall, the tested methodology is effective, but will need to be sharpened in the future. The results also offer starting points for future research to further deepen the path taken here.