Peer pressure, too, plays a powerful role in fostering high academic performance. The influence of peers, which tends to peak at ages 15–18, has been shown on teens’ academic achievement, educational aspirations, college going, misbehavior, drug use, truancy, and depression, as well as consumer behavior. As peers transmit social norms, educational values, and even academic skills, peers at high-income schools thus serve as educational catalysts for one another. High standards and aspirations tend to be contagious—as do low standards and aspirations.38 Peer pressure helps explain the correlation between a school’s socioeconomic composition and student performance.³⁹

But where do the affluent kids’ standards and aspirations come from? Isabella gave us a clear answer—the parents. “[My parents] didn’t try to put a lot of pressure on me, [but] a lot of people have got pressure on them from home. . . . [When] kids would not do as well as they had wanted to do on a test, they wouldn’t want to go home, because their parents would be waiting there to say, ‘Okay, let me see your score. What’s wrong?’ ”

The net result in a school with lots of kids from well-educated, academically ambitious homes is that peer pressure—what Isabella and her classmates experience as “stress” and “competition”—amplifies the collective effects of the achievement motivation from their homes. Conversely, in a school like Santa Ana the peer environment dampens whatever academic aspirations any individual student might bring from home.

So, on average, what kids from affluent homes and neighborhoods bring to school tends to encourage higher achievement among all students at those schools. But the opposite is also true: the disorder and violence that kids from impoverished homes and neighborhoods tend to bring to their schools discourages achievement for all students at those schools. This is what we saw happening at Santa Ana High, with students whispering threats of mayhem in the classroom, and teachers confining themselves to baby-sitting.

High-poverty schools are characterized by higher rates of delinquency, truancy, disorder, and transience than low-poverty schools, and lower rates of English proficiency, because all of those characteristics are concentrated in poor communities.40 As we witnessed in Santa Ana High, all those characteristics adversely affect all the students in such schools, whether or not they personally are delinquent, truant, disorderly, transient, or non-English-speaking. One careful study, for example, found that the presence in a classroom of kids who had been exposed to domestic violence reduced other kids’ achievement, especially in high-poverty schools.⁴¹

Here, too, the class gap seems to have grown in recent years, yet again creating the familiar scissors effect. Between 1995 and 2005, victimizations at school declined by nearly 60 percent in suburban schools but by only 43 percent in urban schools. Not surprisingly, too, graduation rates are much lower in high schools with more crime-prone students, because of their impact on class climate and on teacher commitment. “Despite aggregate declines in school crime and fear,” criminologists David Kirk and Robert Sampson conclude, “inequality by race and social class in educational experiences has likely increased because declines have been relatively more concentrated in suburban and private schools.”⁴²

Gangs, largely an urban phenomenon, contribute significantly to school crime and fear. Roughly one quarter of urban students report a gang presence at their high schools, and about one quarter of urban schools report 20 or more violent incidents annually.⁴³ Most of those incidents are not reported to police, but, as Figure 4.2 shows, suspensions are two and a half times more common in high-poverty high schools than in low-poverty high schools. We saw an extreme version of this disparity when (in Table 4.1) we compared the rates of suspension at Troy High and Santa Ana High. An even greater concentration of disciplinary problems in high-poverty schools is found among elementary and middle schools, though suspensions are rarer in the earlier grades.⁴⁴

The result of this concatenation of disadvantage, other researchers have found, is that “high-poverty classrooms have four times the concentrations of academic, attention, and behavioral problems as low-poverty classrooms.”45 This is, of course, precisely the school climate that Sofia and Lola described for us in such harrowing detail: a climate that disrupts class management, student learning, and teacher morale, and lowers the odds that teachers with other options will choose to work or stay in such schools.