Or maybe the lessons that are most important in high school aren't measured effectively on the test. They could be intangibles that are untestable, or the test

Or maybe the lessons that are most important in high school aren't measured effectively on the test. They could be intangibles that are untestable, or the tests could just be flawed. Of the middle/HS teachers I know, those in nice school districts regard tests as a pain and a distraction, but the ones from poor school districts hate them. Apparently the way the tests are written, your typical black or ESL city-dweller could understand the material extremely well but the questions are very much in white suburban english, and reference cultural context that they're unlikely to understand. Add in a little intimidation and mistrust, and you've got test results that are basically irrelevant to whether the kids know the material.