This report estimates the effect of enrolling in a charter school on student standardized test scores in Newark, New Jersey. The results indicate that attending a Newark charter school that participated in the city's common enrollment system leads to large improvements in math and reading scores, and the effect is especially large for students who attend a charter school run by either the Knowledge Is Power Program (KIPP) or Uncommon public schools networks. The analysis is based on data from the first two years of the city's common enrollment system, which uses the deferred acceptance (DA) mechanism to assign students to all traditional public and magnet schools, as well as most charters. Major findings include: (1) Enrollment in a Newark charter school that participated in the common enrollment system leads to large improvements in math and English language arts (ELA) test scores, on average; (2) There are potential differences in the effect of enrolling in a charter school by student subgroup, such as race, gender, or qualification for free lunch. However, due to the smaller sample sizes, these models are estimated too imprecisely to detect such differences as statistically significant; and (3) Students who enrolled in a charter school operated by either the KIPP or Uncommon national charter school networks experienced especially large effects. When considered as a group, participating charter schools operated by other entities produce some gains, though of a smaller magnitude.