Supporters promise that school choice will revolutionize schools. Opponents say it will destroy public education. Meanwhile, with little fanfare, Arizona has initiated a free market in public education. With the most pro-choice policies in the nation, Arizona has 350 charter school campuses.

Charter schools are public schools that are self-governed and market-driven, much as private schools are. Charter operators determine curriculum, hire and fire teachers, and earn funding based on the number of parents who choose their school. But unlike private schools, charter schools cannot impose religion, charge tuition or deny admissions.

Our evaluation of Arizona's experiment in free-market education finds that while choice is no panacea, it has made schools more accountable to parents and has empowered many teachers.

Parents who want educational alternatives are big winners under choice. School choice has popularized options including Montessori, core knowledge, back-to-basics and Waldorf programs. These were previously unknown in Arizona or available only at private schools for a hefty tuition. Preliminary analyses of Phoenix elementary schools suggest that charter enrollments reflect not "white flight" but a demand for such educational alternatives.

Still, we doubt that charter schools will replace district schools. After three years of exponential expansion, charter enrollment growth slowed to 31 percent from 1997 to 1998, with a similar increase expected this year. Nearly 95 percent of Arizona public school students remain in district schools, because many districts do a fine job. We expect charter enrollments to stabilize at 7 percent to 15 percent of district enrollments, with higher percentages where district schools displease parents.

Charter schools don't replace district schools, but they do push district schools to compete. In Arizona, state subsidies follow the students, so charter enrollments are watched closely by district school administrators who fear loss of students -- i.e., of money. Asked about the impact of charters, one district official stated, "We have lost 250 [children] to charters so there's one impact, an economic one; $3,500 a kid is the princely sum the state of Arizona gives for each child."

Some district schools react to competition by advertising, opening magnet schools and changing curriculum. In short, competition pushes many district schools to work to win back charter parents.

To help parents choose schools, the Arizona Department of Education posts report cards for all public schools on the Internet. These list school test scores, curriculum, mission statements and other data. In addition, failing charter schools are held accountable. In the past four years, 19 of 290 charter campuses folded, either because parents pulled out their children or because state regulators closed the schools. In contrast, failing district schools remain open.

Many teachers do well in an education marketplace. Surveys show that, compared with teachers in district schools, charter teachers have more collegial relations with colleagues and parents, and have far more power over curriculum. In charter schools, principals, teachers and parents are in charge; school boards and central offices do not even exist.

We find evidence that some district school principals empower their teachers in response to charter competition. In Arizona and nationally, the best charter schools are started by entrepreneurial teachers who felt stymied by school administrators and school boards. For example, Arizona Teacher of the Year Karen Butterfield could not gain district backing for a new program and so instead opened a charter school. We suspect that from now on, district schools will be more likely to say yes to teachers bearing ideas to keep them from joining the competition.

Not all the news is rosy. Some of Arizona's school districts have not reformed to meet charter competition. The Arizona Department of Education needs more resources to ensure that school report cards are accurate and to provide transportation assistance to low-income parents. The freedom that allows hundreds of successful charter schools also allows a few incompetent operations, not all of which are closed in a timely fashion. Most important, data are insufficient to determine whether competition improves test scores.

School choice is no panacea, but Arizona has shown that school choice is viable. Parental choice is likely to improve education even for children who stay in the district schools. As fathers, we wish we had the freedom to choose our children's schools -- something most Arizona parents can take for granted.

Robert Maranto is a visiting scholar in the Curry School of Education at the University of Virginia. Scott Milliman teaches economics at James Madison University.