With 20 years of PBL teaching experience, Carmel Schettino can speak to the many ways that teachers have adapted various student-centered pedagogies and problem-based curricula to a form what they called problem-based learning. In the past 5-8 years PBL has seen a rise in popularity and use in many disciplines, but the research surrounding the learning that happens in the mathematics classroom is not catching up with anecdotal support for the teaching method. In this session, we'll discuss differences between Problem-Based (PBL), Project-Based (PjBL and Inquiry-Based Learning (IBL) from a researcher's standpoint, as well as what is known about PBL in terms of student learning in mathematics.