Academic journal article The Future of Children

Charter Schools and the Achievement Gap

Academic journal article The Future of Children

Charter Schools and the Achievement Gap

Article excerpt

Charter Schools in the United States

Charter schools are public schools that operate with autonomy from traditional school districts. They are given flexibility in curriculum, structure of the school day and year, and budget management, and are not required to participate in collective bargaining. In exchange for this flexibility, charters are held accountable by their authorizers (state education agencies or organizations like colleges, special boards, or even school districts, depending on the state), who can revoke these schools' chatters if they don't meet state standards. Charter schools are free and open to the public. If more students wish to attend a charter school than there are seats available, admission is by lottery.

The first chatter schools were created in Minnesota in 1993. Forty-three states and Washington, DC, now have laws that permit the operation of chatter schools, and around 7,000 charter schools now serve more them 5 percent of students in the United States. (1) They've grown steadily over the past 10 years, adding about 300 or 400 schools each year. To put this in perspective, about 10 percent of US students attend a private school, and 3 percent are homeschooled. Despite the relatively small size of the charter school sector, charter schools and their effects on students have been a large part of the education policy conversation in the past two decades. Though charter schools were originally envisioned as laboratories for testing educational practices, their proponents currently value them as an outlet for students and families who are dissatisfied with traditional public schools. (2) Additionally, advocates claim that increasing competition by allowing students to vote with their feet may improve systemwide performance.

The Impact of Attending a Charter School

Researchers who wish to assess how attending a charter school affects student achievement face a common problem in social science research: selection bias. You could simply compare the test scores of students in charter schools with those in traditional public schools, but that would be misleading. Charter school students have chosen this alternative, and thus they may be different from their peers in traditional public schools. If you saw differences in test scores between charter and traditional public schools, you couldn't say whether they were caused by differences in schooling or by differences in the type of students who attend charters. It's not hard to imagine that students who choose to attend charter schools are different from those who don't. For example, their families were motivated to seek an educational opportunity for their children outside the norm. Consequently, if chatter students had higher test scores, it may simply reflect the fact that they're the type of students who attend a charter school, rather than saying anything about the school itself.

Happily, many charter schools have a built-in mechanism to overcome the selection-bias problem. Because charter schools are required by law to admit students by a random lottery if they're oversubscribed, charter school admissions are analogous to an experiment in which participants are randomly assigned to a treatment group or a control group (a randomized controlled trial). After accounting for important details that arise from operating a lottery in the real world versus doing so purely for research purposes, such as sibling preferences and late applicants, a random lottery assigns the seats for charter schools that are oversubscribed. This allows researchers to compare the outcomes of a treatment group of students who were offered a seat in the lottery to a control group of those who were not. To estimate the effect of attending a charter school (as opposed to applying to a charter school), researchers divide the treatment-control test score difference by the difference in attendance rates. The benefit of this approach is that the random lottery ensures that the two groups have similar observed and unobservable characteristics, and therefore any differences in outcomes can be attributed to attending a charter school rather than to unobserved differences among the students. …

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