A great blog post called "5 Stereotypes about poor families and education" in the Washington Post a few days ago quoted extensively from a book by Paul C. Gorski titled Reaching and Teaching Students in Poverty. The excerpt offers a lot of research to dispel some common negative myths about poor people that impact the way schools and educators tend to approach them and how that impacts their experience of school; poor people don't value education, poor people are lazy, poor people are more likely to be substance abusers, poor people are linguistically impoverished and -- the biggy -- poor people are ineffective parents.
This is a tricky subject because some things about poverty can have an impact on kids' school performance as well as physical and mental health. Well-intentioned governments and schools generally want to respond to those negative effects in order to ensure that kids growing up in poverty have the best opportunities they can (or say they do, at any rate). But as Gorski points out fuzzy thinking about how exactly poverty does or doesn't impact kids and families can be deleterious on a classroom or a public policy level.
The WP post doesn't discuss the tings we do know about the ways in which poverty (or things that are highly correlated with it) impact kids and families though I am assuming the book will do just that. Paul Tough wrote a great piece a few years ago for the New Yorker called "The Poverty Clinic." The article looked at a medical clinic which used the findings of the Kaiser Permanente Adverse Childhood Experiences study to treat poor families. The upshot of the study and Tough's article is that childhood trauma is a huge risk factor for both physical and psychological illness both in childhood and in later life. Since poor people are much less well insulated against trauma, they are, on average, at greater risk. Trauma both intensity and frequency are a great predictor of difficulty in school and later life, but not poverty per se.
The other piece of really interesting research about differences in family style between poor and middle-class families and how that impacts education that Gorski alludes to in the extract, but that doesn't get a lot of play is Anette Lareau's distinction between middle-class "concerted cultivation" versus poor and working class "accomplishment of natural growth." While not contradicting Gorski, Lareau does portray the poor/working class families in her study as less organized around talk and less at ease with certain kinds of parent involvement (Gorski says that poor families may want to be involved but may feel turned-off by the ways schools invite participation, which tends to be geared towards middle-class parents).
Finally, one of the things that Gorski doesn't address in the blog post is varieties of poverty. Because poverty itself is not the cause of academic failure or ill health or family dysfunction, but certain things that are often associated with poverty are risk factors for all those things, we should look at and think about the way differences between poverties impact those factors; for example, not every poor community increases exposure to trauma for kids. Some poor communities are better at insulating their young against trauma than some wealthier communities.