(This is the third post in a four-part series about Common Core. PART ONE/PART TWO.)

In the last two posts, we’ve talked about the potential benefits and pitfalls of the Common Core standards when it comes to the quality of children’s education. But there’s a big question that we’ve glossed over: which children? Levels of student achievement in the U.S. are deeply connected with race and income levels, and any educational reform effort needs to take that fact into account.

Just how divided is the country? Writing in The Future of Children in 2009, Robert Balfanz notes that 96 percent of students in the nation’s 50 wealthiest school districts graduate, compared with 64 percent in the 50 poorest districts.

“National Assessment of Educational Progress (NAEP) scores indicate that high-poverty eighth graders have skill profiles closer to the average fourth grader than the average eighth grader,” he writes.

Part of the issue is school funding. Districts serving poor students, as well as African Americans and Latinos, are less likely to be well funded than those in wealthy, largely white areas.

“At the extreme, it is possible, particularly in northern cities and their surrounding suburbs, to find two high schools within ten miles of each other with one spending $15,000 per pupil and the other $5,000,” Balfanz writes.

Even writing in the pre-Common Core era, Balfanz noted big changes in school standards between the 1980s and 2000s, with many schools making it more difficult to graduate, or even to be promoted to the next grade. The impact on poor students and students of color from these reforms has been mixed.

“Overall, available evidence suggests that the nation’s low-performing high schools can be improved, though reform is difficult and often uneven,” he writes.

The complexity involved in improving student achievement at schools with lots of disadvantaged students is laid out in The High School Journal in a paper summarizing a 2006 conference on high poverty schools. Author Howard Machtinger writes that there are three basic perspectives on the issue. One holds that resources must be distributed more equally among the nation’s schools. The second argues that, since some high-poverty schools succeed despite the odds, the lack of resources shouldn’t be treated as an excuse for low performance. The last points to barriers to student success that arise outside the classroom and calls for not just school reform but new social policies and economic opportunities.

Conference attendees discussed a variety of possible reforms, from providing financial incentives for excellent teachers to work in high poverty schools to new desegregation efforts, either on the traditional basis of race or along economic lines. Some also pointed to the importance of high expectations and methods of teaching that respect students’ cultures. Noting that lessons offering real intellectual challenges are generally found to be better than rote memorization, both in terms of students test scores and in more comprehensive measures, Machtinger questions why many low-income schools continue to go the “drill and kill” route.

“Do administrators and schools not know about or believe the research? Or do racism and classism trump these findings with deep-seated beliefs about certain groups’ academic and intellectual incapacity?” he writes.

When you start talking about ways to improve education for low-income students and students of color, you can’t go very far before running into the Harlem Children’s Zone. Combining public funds and philanthropic donations, HCZ provides an array of social services like parenting support, preschool and health programs, along with three charter schools, within a 97-block section of Harlem. The idea is that these wrap-around services can address children’s basic needs, making success at school more likely.

HCZ has been widely promoted as a model for other programs, despite some criticisms of its high teacher turnover and dependence on private funding. But there’s debate about how exactly it works. A 2011 paper in the American Economic Journal: Applied Economics by Will Dobbie and Roland G. Fryer Jr. tried to separate the effects of attending the program’s Promise Academy charter schools from the social programs surrounding them, concluding that the schools, not the services, were responsible for the higher student achievement.

First, students who live outside the Zone garner the same benefit from attending the Promise Academy as the students inside the Zone, suggesting that proximity to the community programs is not important,” the authors wrote. “Second, siblings of Promise Academy students who have access to the same community programs but were ineligible for the Promise Academy because of their age show no detectable gains in achievement.

Can that conclusion guide public policy? Writing in The Phil Delta Kappan, Thomas Touch warns against giving Dobbie and Fryer’s analysis too much weight. Touch notes that the question of whether outside services are necessary exposes a fault line among school reformers. Some worry that a fatalistic outlook about students’ life circumstances could lead to the lowering of standards. Others—even some leaders of prominent “no-excuses” charter schools—say that, realistically, they must respond to students’ needs outside the classroom, even if it’s on an informal basis. He quotes a co-founder of another widely lauded charter school program, KIPP, saying that the HCZ services are preferable to the way KIPP schools must respond to students’ problems outside the classroom “one crisis at a time.”

“At the very least,” Touch concludes, “We should try a number of experiments, study them carefully, as the Administration proposes, and see what we learn, rather than relying on the findings of a single study of a single school.”

The most appropriate viewpoint on the challenges affecting disadvantaged students may depend partly on who’s doing the looking. For school teachers and administrators with little influence outside the classroom, it might make more sense to focus on improving instruction. For people working to affect government policies, on the other hand, considering unequal school funding and deeper questions about the destabilizing effects of poverty seems advisable.

As implementation of Common Core standards moves forward, the question of how to help students of color and those from low-income families succeed on its terms—which largely means doing well on new standardized tests—will be front and center. But so will another question, which we’ll address in the next and final post in this series: How much can test scores really tell us, anyway?