In the spirit of model revision, researchers continue to refine the notion of a learning progression. Despite many advances in learning progressions research, one key design element has eluded scholarly critique, the upper anchor. Drawing on science education research and studies of science, this essay argues for a shift from the predominant model…

Learning progressions (LPs) are hypothetical models of how learning in a domain develops over time with appropriate instruction. In the domain of genetics, there are two independently developed alternative LPs. The main difference between the two progressions hinges on their assumptions regarding the accessibility of classical (Mendelian) versus…