The image of a little black girl being escorted to public school by U.S. troops has been seared in the collective American memory.

But now, some educators are saying that the issue of desegregation should never have been based on the color of the girl's skin. Instead, they say, the issue should have been whether she was holding free-lunch tickets.

Forty years ago, "integration" referred to the federally mandated way of improving education for minority students. Now, some educators say school quality may have less to do with race than with economics. And in some schools, the students who benefit aren't differentiated by their skin color, but by free lunches.

"Schools that are over 40 percent 'high-needs' students suffer," Wake County Public Schools Associate School System Superintendent Walt Sherlin said.

The Raleigh, N.C., school system is part of a small but growing number of school districts experimenting with economic desegregation, including Cambridge, Mass., La Crosse, Wis., Charlotte, N.C., and San Francisco. What school children go to doesn't depend on their race, but on whether or not they're enrolled in free-lunch programs. Some poor children will be sent to schools to be with more children from middle-class and wealthy families. And some well-to-do youngsters will be sent to schools to be with more poor people.

"Low-income students who attend middle-class schools are much more likely to go on to college," the Century Foundation's Richard Kahlenberg said. "And part of that has to do with what their peers are doing.

"It's highly insulting to say that African-American or Latino kids need to sit next to whites in order to learn," he said.

In Cambridge, officials looked at how many children in each elementary school are enrolled in free-lunch programs. The citywide average per school is about 48 percent, but in some schools the rate was as low as 20 percent and in others as high as 88 percent, Superintendent Bobbie D'Alessandro said. They decided their goal was to bring the number free-lunch students in each school to within 5 percent of the citywide average.

"I feel fairly passionate that we need to equalize the system and this is a good way to do this," said Rick Colbath-Hess, a 42-year-old white social worker who has two children in the Cambridge schools and whose wife is a third-grade teacher. "I think there are going to be many cities watching us. If it works it will be copied."

Cambridge will begin desegregating with the kindergarten class entering in September.

In La Crosse, the first city to try out economic segregation, test scores at both regular high schools improved, Jerry Kember, superintendent of the 7,800-student La Crosse system, said.

"When you put poor children among only other poor children, they lose vision of what's possible," he said. "When they come back from summer vacation, they don't hear stories of vacations in Europe."

And it actually also helps the wealthier kids, he said.

"They understand the human condition for others when they go to school with kids of all backgrounds and from all parts of town," Kember said.

But there's still a correlation between race and income, and educators and parents are still debating whether moving higher-income kids into struggling schools will improve education for everyone or make wealthier kids pay a price. Critics say economic desegregation is just a creative way of maintaining racial quotas and busing programs despite recent court decisions against them.

"It's about your parents and your communities being involved in raising your children," Raleigh parent Debra Carlton said. "And when you take a child out of their own neighborhood and their support network, they're not going to have that level of support that they need. I can't volunteer when my daughter goes to this new school. It's three times further away from my house."

Other parents fear it will lead to white flight and a "dumbing down" of classroom instruction for the benefit of the poor youngsters.

Cambridge mother Maria Hanlon, with children in the fifth and sixth grade, said the new system could mean families pulling their kids out because they will not be able to place them in the most desirable schools.

"It's just one more misguided effort unless most schools present a viable option for more families," she said.

But Sherlin said there's a bigger picture that can't be ignored.

"One of the problems, I think, with pure neighborhood schools is some schools are really good and really successful, but other schools really struggle," he said.

The Associated Press contributed to this report.

Jonathan Serrie joined Fox News Channel (FNC) in April 1999 and currently serves as a correspondent based in the Atlanta bureau.