In his landmark study of American schools, sociologist James S. Coleman arrived at a startling conclusion: “The educational resources provided by a child’s fellow students are more important for his achievement than are the resources provided by the school board.”

Fifty years ago this month, Coleman delivered the "Equality of Educational Opportunity" study to Congress, which commissioned it as part of the 1964 Civil Rights Act. The assumption had been that racial segregation explained the gaps in student performance, but the Coleman Report pointed to socioeconomic segregation as the greater impediment to children's learning.

“A child’s learning is a function more of the characteristics of his classmates than those of the teacher,” said Coleman. “Particular individuals who might never consider dropping out if they were in a different high school might decide to drop out if they attended a school where many boys and girls did so.”

The idea that peers influenced achievement more than teachers or school spending was brand new. Rather than race, the study fixed on social class as a more effective lever for equality of outcomes. A half-century later, Americans seem resistant to using either race or class to diversify their schools.

Schools are more racially segregated today than in the 1970s. About 8 percent of public school students attend school districts or charter schools that now use socioeconomic status as a factor in student assignment, according to the report, "A New Wave of School Integration," released earlier this year by the Century Foundation.

“Part of the reason for this surge in racial segregation is that American communities are increasingly stratified by social class…Socioeconomic and racial segregation have become related and often overlapping phenomena," states the report.

Despite evidence that higher-income students don’t lose ground when they share classrooms with lower-income peers, many middle-class parents remain leery of what they consider failed social experiments and prefer to maintain neighborhood schools. It is a battle few school districts are willing to enter, even in liberal bastions.

In 1993, City Schools of Decatur attempted to persuade adjacent white and African-American neighborhoods to voluntarily blend two racially segregated elementary schools that were a mile apart. The superintendent and other school leaders promised they wouldn't mandate changes to the attendance line, but appealed to the conscience of the community, asking for “a redrawing of the line in your hearts.” No one pulled out a pen, metaphorically or otherwise.

Many advocates have given up on changing hearts and minds and hope to transform schools in poor communities by investing more resources and assigning the best teachers. But research suggests even high quality instruction cannot catch poor children up to middle-class peers. When the majority of students begin school already far behind, teachers must devote more time to remediation, and the bright students can be neglected. Schools in poor communities often have more transient students, so teachers lose time bringing new kids up to speed.

Parents in poor schools lack the time or social capital to lobby for higher standards. Consider the recent revelation that 65 students at an Atlanta high school received no grades because a series of substitute teachers never submitted any or gave any graded assignments. No one in authority at the school could be sure what happened, and the incident only came to light after a fired secretary reported it. Had it occurred in Fulton or Forsyth, parents would have stormed the school board.

As Coleman noted 50 years ago, “Cultural dominance of middle-class norms prevail in middle-class schools with a teacher teaching toward those standards and with students striving to maintain those standards.”