The author argues that there is still too much teaching to the test, and the consequence is growing "constellations" of problem-based learning (PBL), some of which are useful, and some of which are not. Today, what passes for PBL practice often seems more like guidelines than any kind of reasoned pedagogy. While at one level the range of variations shows the value and flexibility of PBL as an accommodating, adaptable, and culturally relevant approach to learning, there is relatively little understanding of the impact of these different constellations on student engagement and learning. Nevertheless, these diverse constellations of PBL need to be delineated and understood. The author outlines the constellations, but also suggests that there are a number of issues that have not been considered in relation to the use of PBL.