I can't believe this is news. It is exceedingly obvious that the achievement gap between poor and rich students is directly related to their economic status. http://mattbruenig.com/2011/09/18/on-the-education-reform-mo...Poor children simply lead different lives than rich children due to their differential access to economic resources. Poor children have worse health and are more likely to experience negative neighborhood effects like exposure to drugs, violence, and crime. Further, their parents are more likely to work multiple jobs or irregular hours which reduces the amount of time they are able to spend with them. Poverty also increases stress both on the parents and the children. These are just a few of the consequences of economic inequality, all of which plausibly impact student success at school.
This is how I feel too. I have been thinking about this a lot lately, and it seems to me that people have little to no insight about the lifestyles of people who live outside of their social class. Which kind of makes sense, because for the most part, people only interact with other people within their own social class, meaning it's really easy for anyone to assume that everyone has a lifestyle that is similar to his or her own. This makes it easy for people to look at poor children and say, "the reason they're doing poorly in school is because they're not working hard enough," or "they're not achieving because they're not smart," when really, these people are just not understanding that having limited access to economic resources makes every aspect of living more difficult.
Part of American mythology is believing that social class doesn't matter very much. For example, I'm sure you've heard people nonironically claim they want "equality of opportunity, not equality of outcome." That is, the only way to avoid crushing levels of cognitive dissonance between, on the one hand, valuing "equality of opportunity," and on the other, being opposed to "wealth redistribution," is to believe that wealth has little to do with opportunity.