Up until now, very few models conceptualizing students’ competence in evaluation, argumentation and discourse in the context of science education have been proposed. Most suggestions for analyzing this particular competence in students are normative and the empirical support for them remains weak. The problem becomes even more severe when such evaluations include ethical and societal perspectives as part of the analytical parameters. In support of this topic, this paper presents two approaches for handling students’ evaluation capabilities in the context of multidimensional discussion situations. One approach focuses on the quality of learners’ arguments concerning levels of justification; the second reflects upon the quality of pupils’ complexity of argumentation. Both approaches were created using group discussion data collected for evaluation purposes. The data stems from a curriculum innovation project focusing on the teaching of climate change in four teaching domains: Biology, Chemistry, Physics and Politics. Participants from 20 different learning groups conducted semi-structured, pre- and post-group discussions on the issue of climate change. Analysis of a total of 76 group discussions showed positive potential in both evaluation grids on the topic.