Facilitating Argumentation in the Laboratory: The Challenges of Claim Change and Justification by Theory WalkerJoi Phelps Van DuzorAndrea Gay LowerMeghan A. 2019 Scientific argumentation is a key means by which students make sense of content and processes in inquiry-based instruction. In scientific argumentation students make a <i>claim</i> that they support with <i>evidence</i> and provide <i>reasoning</i> as to how the evidence supports the claim. Integrating the different aspects of scientific argumentation can be challenging for students especially if they need to make a claim change to accommodate new evidence. This study examines student argumentation within a two-semester general chemistry laboratory sequence at a minority-serving, comprehensive university in the Midwest, which employed the Argument-Driven Inquiry (ADI) instructional model for laboratory instruction. Video recordings of group argumentation from four investigations, two each semester, were coded using the Assessment of Scientific Argumentation in the Classroom (ASAC) observation protocol. On the basis of the data, students did not tend to change their claims or reasoning even when provided with contradictory evidence. Semistructured interviews with students also coded with the ASAC revealed that students did not view claim change as a valid component of argumentation.