The only outcome these tests produce is better test-takers. And that result is gleefully measured and interpreted to be education. Little meaning can be divined from the test scores of students who are headed to success despite what schools have not achieved for them. Much more can be learned from the populations for whom school has failed. To learn what has to be done to fix education, you need to study prison populations.
Prisons collect socio-paths, fools and the failures of education.
About two-thirds of America's prison population is illiterate. Most of them got that way courtesy of the public schools. During the mid-nineties the U.S. Education Statistics published Literacy Behind Prison Walls. The NAAL and these derivative reports judged prisoners on their writing, their ability to comprehend documents like maps, and their quantitative literacy. About one-quarter of all prisoners are incarcerated for drug related crimes.