More than half of public school students are now low income. What does that mean for schools?

The Southern Education Foundation released a research bulletin today on the increase in low-income students in our nation's public schools.

Low income students are now a majority of the children in America's classrooms.

This change comes at a time when we have higher performance expectations for our students. Those expectations will be harder to meet because low-income students bring more challenges to the classroom.

Stanford researchers have found the gap in test scores between affluent and low-income students has increased by nearly 40 percent since the 1960s.  (The score gap between rich and poor is now twice that of the black/white score gap.)

The Stanford research by Sean Reardon is interesting; it is not that schools are failing low-income kids; academic performance is, in fact, improving. However, the performance of rich kids is outstripping not only poor children, but middle-class students as well.

Why? One reason may be because their parents are investing heavily in their success, including providing top preschools and enrichment opportunities. (Anybody read about the SAT prep tutor in New York who charges $1,500 for 90 minutes and requires kids take at least 14 sessions? I'll do the math for you -- $21,000. For that, parents get a promise their child's score will rise an average of 400 points.)

As Reardon writes, "Family income is now nearly as strong a parental education in predicting children's achievement."

Greg J. Duncan and Richard J. Murnane, authors of  "Whither Opportunity,"  write, " the incomes of affluent and poor American families have diverged over the past three decades, so too have the educational outcomes of the children in these families. Test score differences between rich and poor children are much larger now than 30 years ago, as are differences in rates of college attendance and college graduation."

New research is highlighting the increased chronic stress experienced by children growing up poor in America.

As Eric Jensen, author of "Teaching with Poverty in Mind," notes:

This kind of stress exerts a devastating, insidious influence on children's physical, psychological, emotional, and cognitive functioning—areas that affect brain development, academic success, and social competence. Students subjected to such stress may lack crucial coping skills and experience significant behavioral and academic problems in school.

Children in low-income homes are less likely to have parents who can provide stability and guidance.

Jensen writes: Socioeconomic status correlates positively with good parenting, which, research has found, improves academic achievement (DeGarmo, Forgatch, & Martinez, 1999). Unfortunately, the converse is also true: the chronic stress of poverty impairs parenting skills, and disengaged or negative parenting in turn impairs children's school performance. Parents who are struggling just to stay afloat tend to work extra hours, odd shifts, or multiple jobs and are less able to provide attention and affection and to devote their time, energy, and resources to their children. These deficits have been associated with higher levels of externalizing behaviors and poor academic performance on children's part (Hsuch & Yoshikawa, 2007).

With that bit of background, here is the bulletin from SEF:

In 40 of the 50 states, low income students comprised no less than 40 percent of all public schoolchildren. In 21 states, children eligible for free or reduced-price lunches were a majority of the students in 2013.

Most of the states with a majority of low income students are found in the South and the West. Thirteen of the 21 states with a majority of low income students in 2013 were located in the South, and six of the other 21 states were in the West.

Mississippi led the nation with the highest rate: ­71 percent, almost three out of every four public school children in Mississippi, were low-income. The nation's second highest rate was found in New Mexico, where 68 percent of all public school students were low income in 2013.

This defining moment in America's public education has been developing over several decades, and SEF has documented the trends and implications in two prior reports.

In its 2013 report, SEF Vice President Steve Suitts wrote:  "No longer can we consider the problems and needs of low income students simply a matter of fairness...  Their success or failure in the public schools will determine the entire body of human capital and educational potential that the nation will possess in the future. Without improving the educational support that the nation provides its low income students - students with the largest needs and usually with the least support -- the trends of the last decade will be prologue for a nation not at risk, but a nation in decline..."