Charting Gaps and Gains
The following charts compare the mathematics performance on NAEP of 4th graders eligible and inligible for free school lunches in "State A" between 1996 and 2000.
The first chart shows that the performance of both groups has improved during that time across the entire range of test-takers, because both curves have moved to the right. The second chart shows that the achievement gap between the two groups also has narrowed. For example, the gap between students at the 30th percentile decreased from 26 points in 1996 to 20 points in 2000.
Source: National Assessment Governing Board, 2002
Vol. 21, Issue 26, Page 11