Since the inception of charter schools over a decade ago, policymakers have wanted to know how charter schools are performing. This is difficult to answer because there is no single charter school approach to educating students. By design, charter schools have innovative and distinctive education philosophies. In this research, we capture some of the uniqueness of charter schools by clustering them into four major categories: charter schools that convert from conventional public schools, charter schools that start from scratch, charter schools that rely primarily on classroom-based instruction, and charter schools that have a significant portion of instruction outside of the classroom. Based on these four distinctions, we find significant differences in performance. These differences suggest that policymakers may want to focus greater resources on certain types of charter schools versus others.