There also is the effect that the <i>grouping</i> matters - other things being equal, your kid will succeed more when put in a class where other students have higher parental investment, rather than when put in class with a lot of poor students having issues with absenteeism and higher incidence crime and&#x2F;or substance abuse.<p>In essence, people are willing to pay a premium in real estate prices just so their kids would not grow in a community of kids who cannot afford this premium.