Learning progressions (LPs) are theoretical models of how learners develop expertise in a domain over extended periods of time. Recent policy reports have touted LPs as a promising approach to aligning standards, curriculum, and assessment. However, the scholarship on LPs is relatively sparse, and the jury is still out on the theoretical and…

Examines how problem solving in the domain of Mendelian genetics proceeds in situations where solvers' mental models are insufficient to solve problems at hand (model-revising problem solving). The study addressed the heuristics characteristic of successful model-revising problem solving and other aspects of student model use. (LZ)