Students who spend time learning pap or rubbish to pass a test have no time to study any subject in depth.
Having no time to learn any subject in depth, means that students will leave school having memorized, and mostly forgotten, a smattering of disconnected "data" that may or may not actually be "factual".
In other words, they will not only have not learned anything useful, they won't have developed any learning skills.
No Child Left Behind and Race To The Top are not about assessing learning. They are about making certain that no real learning occurs.