History educationalists internationally agree on describing historical thinking and learning on the basis of narrative theoretical models. However, it is striking that there is often a significant difference between rigorous, demanding theoretical and normative expectations, and disappointing empirical results. In the context of the student dissertation project presented here, a substantially wide range of essays has been chosen. More than 1,100 essays from history students between the ages of 7 and 21, with an average length of 33 pages, provide the foundation of this research project. Considering the amount of relevant data (the essays, and submissions using other genres) involved, we developed as a methodological evaluation tool a mixed-methods approach with an explanatory three-phase design (QUANT – QUANT/QUAL – QUAL). This paper presents theoretical and methodological approaches drawing upon examples plus exemplary results of the quantitative and qualitative evaluation of student essays. Thus, we present for discussion the potential of the research field for mixed-methods research.