Here is one paragraph from an article that appeared in the Autumn 2014 issue of City Journal. The writer is Kay S. Hymowitz and the subtitle states : Families shape their children’s prospects more profoundly than anything government can do.

Universal preschool is by far the most popular idea for easing poor children’s early disadvantages. The theory behind it is similar to the argument for parenting programs: if we give low-income children a middle-class, school-relevant experience when they’re young and impressionable, they will be as prepared for school as middle-class kids are. Yet since the 1960s, when Head Start got under way, preschool’s effect on children’s academic futures has ranged from nil to modest. A notable paper by Brian Jacob and Jens Ludwig concludes that even when cost-effective, preschool programs don’t significantly reduce the achievement gap. The biggest problem is what researchers call “fade out.” In some of the best programs, children appear to be as “school ready” as middle-class kids. By third grade, however, they revert to the same academic levels as their non-preschooled, low-income peers. Experts have struggled to account for fade out, but one likely explanation is that whatever educational habits these preschools impart are not reinforced in the homes of low-income children and in the elementary schools that they go on to attend.