I think that they are misrepresenting whatever data they have.

MCAP has Math testing for grades 1-8, Algebra 1, 2, and Geometry.

So I'd be interested to know what criteria they're using to measure High school and Elementary school proficiency. This strikes me as nothing more than another 'Project Baltimore' gotcha piece to appeal to their base (majority of whom probably aren't proficient enough in math to grasp statistics).

If it's not? Why aren't they providing the data and methodology.