With charter schools now serving approximately one million students nationwide, policymakers have been awaiting rigorous evaluations of their effects on student learning. The following articles help fill the gap. Caroline Hoxby and Jonah Rockoff present evidence from the first randomized evaluation of charter schools, focusing on three charter schools in Chicago. Robert Bifulco and Helen Ladd examine charter schools in the Tar Heel state, concentrating on those students whose progress can be compared in both charter and traditional public schools.
The picture that emerges is, to say the least, complex. But we learn some significant things: Charter schools appear to do better with young students who matriculate directly into these schools than with students who enter during the middle-school years. Students who remain in charter schools do better than those who migrate back and forth between sectors.
Findings from the City of Big Shoulders
Younger Students Learn More in Charter Schools
The number of charter schools has grown very rapidly in the United States, from essentially none in 1990 to more than 3,400 today. Supporters believe that the flexibility granted these new public schools allows them to be more innovative and responsive to student needs than traditional public schools are. And the fact that no student attends a charter school unless his parents want to keep him there means that families can "vote with their feet." When a parent leaves a charter, so does the funding associated with his child. Thus a charter school cannot survive without satisfied parents. But charter schools do not just answer to parents; they must also persuade an authorizer to recharter them every few years, and they must participate in statewide testing and accountability. Will this concoction of flexibility, answering to parents, and accountability to the government raise school quality? Bluntly put, do students in charter schools learn more than their counterparts in traditional public schools? More than they would have learned had they stayed put?
A Lottery-Based Evaluation of Charter Schools
Getting a reliable answer to these questions is vital to the current policy debate, but researchers who try to answer them face considerable obstacles. First and foremost, most charter schools are new and small. They just don't yet have enough results for researchers to draw conclusions. Second, although all charter schools share the features mentioned above, they are otherwise a diverse lot. Many set up shop in urban areas, serve minority and low-income students, and rely on a strategy and curriculum associated with an education management organization. However, some charter schools serve very rural, mostly white students. Some are run as start-ups by parent or community groups that do not associate themselves with a particular strategy or curriculum. Even within the world of education management organizations, approaches to learning can differ substantially. In short, an assessment of some charter schools is useful for learning about similar charter schools, but we should not expect it to inform us about all charter schools.
Even when researchers can evaluate charter schools that are large enough to contribute useful results to a study, old enough to have a track record, and representative of a substantial share of all charter schools, they face a daunting analytical challenge: finding students in the regular public schools who are truly comparable to the charter school students. Students who apply to attend charter schools are a self-selected group, and simply comparing them with all other students in local public schools is likely to be misleading. We do not even know whether to expect self-selection to work for or against charter schools. On the one hand, parents who try out charter schools may be especially motivated. On the other hand, parents whose children are doing well may avoid being "guinea pigs" in relatively untried schools. …