Tracing Conceptual Development through Trajectory-Embedded Authentic Assessment in Collaborative Physics Learning

Conceptual knowledge development is often inferred from pre- and post-test comparisons, which capture outcomes but provide limited insight into how understanding evolves during the learning process. This study aims to examine how authentic assessment embedded within learning trajectories can make students’ conceptual development visible over time within a collaborative physics learning environment. A hybrid design was employed, combining outcome-based measures with longitudinal analysis of students’ written assessment artifacts. Two groups participated in collaborative physics learning activities, with the experimental group individually completing trajectory-embedded authentic assessment through structured activity sheets aligned with anticipated conceptual pathways. While pre- and post-test results served as reference points, the primary analysis focussed on tracing the progression of students’ individual reasoning across learning phases within the collaborative setting. The findings show that although both groups improved in learning outcomes, trajectory-embedded assessment revealed intermediate reasoning processes, partial conceptual integration, and non-linear development patterns not captured by outcome-based measures alone. Students’ artifacts reflected gradual concept coordination and episodes of instability across representations. These results highlight the value of trajectory-embedded authentic assessment as a process-oriented approach, offering deeper insight into individual conceptual development within collaborative learning contexts and contributing to discussions on assessment validity.