Charles Murray Watch
when first measured in the early 1940s, the gap in reading achievement between children from high and low income families was about 0.60 standard deviations. It subsequently more than doubled to 1.25 standard deviations by 2000.
These income-based achievement gaps are large. To put them in perspective, consider the black-white test score gap as measured by the National Assessment of Education Progress (NAEP) for 13 year olds…That gap was about 1 standard deviation in the 1970s, then fell to about 0.50 during the 1980s where it has remained relatively constant. As a result, the achievement gap between children from high and low income families is now far larger than the gap between black and white children.
…Even in countries such as Korea, Finland and Canada that are typically viewed as having high performing education systems, the patterns hold: achievement levels of the low ESCS children fall far short of those of their more advantaged counterparts.