One of the appealing aspects of the charter school system is the ability for parents to opt out of "mainstream" public schooling for whatever reason. Many charter schools specifically cater to "gifted and talented" children, focusing on fine arts and college preparation. However, this can lead to economic polarization, further alienating communities. Studies have shown that charter school enrollment in Los Angeles, for example, is largely made up of low-income black students. Many charter schools offer no programs for students requiring special education.
The creation of charter schools stipulates that they must demonstrate good performance to justify their relative autonomy. However, in states that allow for charter schooling, what constitutes "performance" is often poorly defined. Public schooling is ostensibly obligated to school boards, standardized testing and the government, whereas charter schools in many places have few, if any restrictions on staff and teachers. Many charter school opponents feel the system is especially vulnerable to political extremism or manipulation by for-profit companies.
The most attractive feature of charter schooling to many is the promise of unconventional learning methods that are more tailored to helping individual students learn at their own pace. Many feel that standardized tests, such as California's STAR program, are rigid, unwieldy and poorly assess the education level of many, if not most, primary school students.
The "charter" referred to in "charter school" is the set of goals that the school uses to shape its teaching methods and student milestones. What unites many of the schools that form under the charter system is empowerment of individual teachers and parents and the encouraging of innovative teaching methods. These schools emphasize smaller schools and smaller classes to ensure personalized learning. Most charter schools are specifically tailored to the outliers in the public schooling system, chiefly troubled and marginal students, and at the other end of the spectrum, artistically gifted or otherwise advanced students.