When an economist first introduced the idea in the 1950s, it was a notion both controversial and contentious. Education, he argued, was a commodity like any other, and would benefit from fierce, free-market competition.
It was a fairly simple idea: Parents and children should become consumers, and schools the product. If a school isn't up to snuff, parents move their children to a better one. Thus good schools flourish and bad ones are forced to improve, or else fall away.
Choice has since become the driving force behind much of education reform in the United States. Charter schools, school vouchers, and the ability to remove kids from failing schools are all attempts to let public education benefit from giving families more choice.
But the theory of choice has faced some difficult reality checks of late. Studies don't necessarily support the claims that students will perform better either in charter schools or in private schools made accessible by vouchers. At the same time, the idea that students should be free to leave failing public schools is bumping up against the simple reality that there are not enough seats in good schools to go around. It's causing some to ask if the growth of the choice movement may not be outpacing evidence of its efficacy.
"While choice is not bad for the individual kids or parents, our experience in New York is that it has done little or nothing to improve neighborhood schools," says Clara Hemphill, director of www.insideschools.org and author of several guides to the city's best public schools. If anything, she says, "it has drained some of the vitality and excitement from neighborhood schools."
Ms. Hemphill says she isn't against choice, "it's just that the market metaphor doesn't work. And I think the New York experience of 30 years is clear on that."
But for many others, choice remains the bedrock of education reform - a tenet not even to be questioned.
"I don't think the debate should be choice or no choice. I think that's absurd," says Henry Levin, a professor at Teachers College at Columbia University. "It's how we do choice."
Choice, of course, can't be viewed as a monolith. It's best understood as a continuum of options beneath the larger umbrella of school choice.
They range from vouchers - which, with little government oversight, allow parents to use taxpayer money at any school, including private or religious - to open enrollment where children may choose from any public school within a certain area, whether a district, city, or even state.
Charter schools, independent public schools that operate with greater autonomy than traditional schools in exchange for a promise to perform, fit somewhere in between. Each has its proponents and detractors, so that a supporter of charter schools, for example, may at the same time oppose vouchers.
But even as the school choice movement surges forward - charter schools can currently be found in 38 states and are expected to be in all states by the end of the decade; 46 states offer open enrollment, up from 32 last year - experts are cautioning that the research to support such robust growth simply isn't there.
Data released last month by the American Federation of Teachers (AFT), indicating that reading and math scores of charter school students on the 2003 National Assessment of Educational Progress lag behind their traditional public school peers, has had the education world up in arms.
In an unusual move, a group of 31 scholars signed on to an ad in The New York Times, where the study first appeared, criticizing its methodology and taking issue with the newspaper's "uncritical coverage."
This week, Caroline M. Hoxby, a professor of economics at Harvard University and one of the undersigned on the Times ad, will release her own more comprehensive study - looking at students in 99.5 percent of charter schools across the country. Professor Hoxby's findings, based on test scores from the same year as the AFT study, show charter school students outperforming traditional public school students in both reading and math.
But in states such as North Carolina, other findings are in line with the AFT results. Helen Ladd, an economics and public policy professor at Duke University, compared gains in test scores made by students in charter schools with those made by the same students while they were in public schools - and found the students performing worse in the charter schools.
With research that's at best contradictory, it's difficult to know how charter schools are performing. For some, this is particularly troubling as President Bush's cornerstone education act, No Child Left Behind, matures. By 2007 sanctions for struggling schools will have kicked in, and those that have failed to meet standards will face, among other things, conversion to charter schools.
The same question mark hanging over charters also punctuates the larger idea of competition among public schools. "One of the issues that we're looking at, but still haven't seen studies to prove, is the idea that competition is the better answer," says Luis Huerta, a professor at Columbia University's Teachers College, who, nonetheless says competition is "a good thing."
Following an extensive look at New Zealand's decade-long experiment with parent choice and competition, Professor Ladd and her husband wrote "When Schools Compete: A Cautionary Tale," which foreshadows some of the problems the US is now struggling with, namely not enough seats in desirable schools.
Still, Ladd says she hopes that "we'll draw on some of the good insights from market-based reform in education."
A tangle of complications has also arisen with open enrollment, one of the oldest and least controversial forms of choice that, according to Cathy Christie of the nonpartisan Education Commission of the States, has come to be accepted as the norm.
This year, 12,000 to 14,000 students in New York City - the nation's largest school system where students may choose from 290 high schools - had no idea in June where they would attend school come fall. Even as the city's education department expanded the number of schools that new ninth-graders could request to attend, some 94,000 students were vying for slots in the most coveted few.
For those able to afford it, choice has long been a part of American education. Parents with the means and wherewithal select neighborhoods to live in based on the quality of schools, and pick up and move if school performance plunges. At its purest, the school choice movement is trying to bring those same options to low-income and minority families.
"The issue then becomes, for me, should all families have the same choice that upper and middle class Americans have," says Ted Sizer, visiting professor of education at Harvard and Brandeis universities. "Or should the system remain as it is, giving mobility to those who could buy it and leaving the rest as they are."
However, Alex Molnar, director of the Education Policy Studies Laboratory at Arizona State University in Tempe, argues that the idea of choice in education is fundamentally flawed. Schools, he says, are "social institutions, not boxes of wheat flakes." Treating them as just another market commodity will never work, he argues.
Barry Schwartz, professor of psychology at Swarthmore College in Pennsylvania and author of "The Paradox of Choice: Why More is Less," agrees. He sees the marketing of education as a "reflection of just how much the ideology of the market as the solution to all problems has penetrated our culture."
Professor Schwartz's research focuses on what he calls "the tyranny of choice" - the destructive psychological toll that a preponderance of options can take. "It seems to me that choice would have to improve the quality of education a lot to be worth the price parents pay," he says.
And while the question of whether choice has in fact improved education has yet to be answered, others say the real concern is that as the choice movement forges ahead, becoming ever more politicized, ideology may come to trump experience.
Despite the numerous studies that emerge, supporting one side or the other, the question of school choice is "not going to be settled on the basis of evidence," says Professor Levin. "Because at the bedrock, at the foundation, it's like window dressing to use these studies to move in one direction or the other. People pick up the evidence that supports their side."