Part of the problem is that NCLB is mandated BUT unfunded for the most part. This is the problem with many federally mandated programs they are burdens to the states with little help coming from the U.S. government. This is unfair, if you write a mandate, help to achieve it's success should, at the very least, be partially funded by those who write the mandate.
Additionally, there are few or no guidelines for schoolbooks each district chooses their own so it tends to be apples to oranges comparisons.
Having a 15 yo son who struggles with ADHD one size fits all doesn't work. I have a difficult time helping him as the way math is taught it's not the correct conclusion that matters it's verbalizing the process. Though I understand that isn't coming up with right answer the most important thing. We might have different ways to come to the right conclusion no single one is more or less correct!