This study investigates how students and teachers perceive learning outcomes when employing an inquiry-based learning approach, and how this relates to two conflicting perspectives on teaching and learning in the Norwegian curriculum. The informants are strategically chosen from among Norwegian elementary schools that use the 'students as researchers' approach, whereby the students develop research questions, form hypotheses, decide which research methods to use, and conduct the research. The conceptualization of learning outcome is connected to the traditions of Didaktik, whereby matter and meaning are separated and the outcome cannot be predicted in advance, and outcome-based education, where the learning outcome is defined in advance as the first element of instructional planning. Twelve semi-structured interviews were conducted, and the data was analysed qualitatively using the NVivo 12 software. Although the students engage with the same subject matter, the results show a considerable variation in what they report having learned. Additionally, the teachers are often unable to plan for the outcomes of the lessons. Our findings therefore emphasize why an awareness of different understandings of teaching and learning is decisive in capturing perceived learning when applying methods such as 'students as researchers'.