This paper backgrounds and illustrates an approach to researching didactic knowledge. Underlying the approach are some of the frameworks developed from the student learning research. Based on these frameworks the experience of learning about a particular phenomenon is theorised as having educationally critical aspects. Without addressing these aspects in learning experiences, students are highly unlikely to achieve the target understanding desired by the teacher. The approach developed to research educationally critical aspects compares scholarly and student experiences of learning about a phenomenon using the analytical framework of a structure of awareness. An application of the approach is reported in the form of a phenomenographic study which researched didactic knowledge about the concept of an information system (IS). Multiple, previously unreported, educationally critical aspects of learning about the concept of an IS were identified. Some implications of this finding for the design of IS undergraduate curricula, textbooks, teaching strategies and learning tasks are proposed. Finally, the research approach is promoted as a means to investigate didactic knowledge about other phenomena.