Though charter schools are revolutionizing U.S. urban education, critics often assert that charters post higher test scores than surrounding traditional public schools because they systematically remove their most difficult-to-educate students. To substantiate this claim, charter critics note that smaller percentages of charter students are enrolled in special education or are classified as English-language learners (ELL) than in traditional public schools, while citing various anti-charter anecdotes supplied by disgruntled parents of former charter students.
- Students with disabilities are more likely to remain in their school if it is a charter than if it is a traditional public school: in Denver, for instance, four years after entry into kindergarten, 65 percent of students with disabilities remained in their charter, compared with 37 percent of such students in traditional public schools.
- Students learning English are more likely to remain in their school if it is a charter than if it is a traditional public school: in New York City, among students classified as English-language learners, 82 percent who originally enrolled in charters for kindergarten remained in their schools four years later, compared with 70 percent of such students in traditional public schools.
- Students with low test scores are as likely to remain in charters as they are to remain in traditional public schools: this result was found in Denver, New York City, and an anonymous urban school district in the Midwest.