This descriptive study by Matthew P. Steinberg and Haisheng Yang documents differences in teacher effectiveness between teachers in traditional public schools and charter schools in Pennsylvania. The authors define teacher effectiveness as the impact that a teacher has on their students’ test score growth (the change in test scores from one year to the next). The authors find that teachers in charter schools run by charter management organizations have higher levels of teacher effectiveness than teachers at traditional public schools and that these teachers tend to improve their effectiveness earlier in their career. However, teachers in standalone charters have lower levels of teacher effectiveness and do not see the same level of early career gains. In both types of charters, teachers have much less experience and are much more likely to exit than in traditional public schools.