The y axis should represent the full range of scale score points from 0 to 500 for reading and math. (edsource.org)
The scores here are a little confusing so let me explain: The numbers you see are how many scale score points away from «meeting standards» the students are. (schooldatanerd.com)
At the 4th grade level in math and reading, D.C. students gained 6 scale score points between 2007 and 2009, while the average gain in the other districts was only 1 point and 2.2 points, respectively. (educationnext.org)