RUME 28
2026
Alexandria, Virginia
Moving Beyond Total Scores With Skill-Proficiency Profiles on Concept Inventories
Page: 521
Research-based assessments (RBAs) are widely used to evaluate student learning in STEM, yet most provide only total scores. We illustrate the value of moving beyond overall performance by applying a cognitive diagnostic (CD) model to student responses on the Precalculus Concept Assessment (PCA) and the Calculus Concept Inventory (CCI). Using 1,366 pre/post responses collected through the LASSO platform, we modeled five key calculus skills: prerequisites, limits, derivatives, applications of derivatives, and introductory integration. Traditional analyses revealed small but statistically significant score increases (d = 0.09 for PCA; d = 0.26 for CCI). CD modeling also showed limited shifts in skill proficiency profiles: students who lacked prerequisite skills did not gain those skills. These results underscore how CDs provide finer-grained evidence than total scores and motivate the development of a Calculus Cognitive Diagnostic to support timely instructional interventions.