Promoting validity of design principles for teaching through educational design research

Educational design research (EDR) needs to further clarify how it leads to valid theoretical results. In this article, we aim to contribute to the development of EDR by suggesting an explication of what validity of design principles for teaching entails, and how the characteristics and phases of EDR can be employed to increase such validity. Our suggestions are based on our own adaptation of EDR within a research program focusing on teaching that promotes students’ mathematical reasoning, informed by discussions and elaborations of EDR and validity of causal inferences. Our results elaborates existing causal validity types in relation to design principles for teaching and adds two new validity types: relative benefit and guiding power. We also describe the importance of employing multi-coder level-raising analysis using an intermediate framework in collaboration with teachers to develop theory over iterations to increase not only explanatory power but also predictive and guiding power.