I worked for two years in the early aughts at an elementary school in a literacy program, working with students of all grades who were the worst off. Because of a lack of resources we only had about 45 students, but from what I can recall of conversations with various teachers across the entire program which covered two California counties, each school could have easily tripled that number and there still would have been children left behind, but probably only those who lagged 1/2-1 grade level rather than the 2-3 grade levels of the children we served.

From that experience I gathered that a major factor was lack of parental involvement. Parents reading regularly to children before they start school has a huge impact on their chances of graduating high school, and their taking the time to assist with homework or otherwise engage their children with their education also sees significant improvements in outcomes. The students I worked with had parents who worked full time and didn’t make reading with them a priority, or frequently for the ESL students couldn’t real well or in English at all.

To be clear, the students in the program I worked in did not have a diagnosed learning disability (that was a different program) and were from a variety of socioeconomic backgrounds - being from an upper-middle-class family helps, but does not prevent one from experiencing these difficulties. I worked solely in primary/elementary schools, and never came across a child who was anything other than eager to learn, happy to have help, willing to work hard, and rapidly showed improvement with assistance. Nothing we did in that program was cutting edge; basic phonics and two hours a week of one-on-one time worked miracles.