Consider...Georgia and neighboring South Carolina.
The two states have nearly identical scores on a national reading test for fourth graders (around 26 percent proficiency) but dramatically different results on their state tests.
South Carolina's fourth-graders had a 36 percent proficiency rating in reading, while Georgia's was 87 percent.
Does this mean kids are reading that much better in Georgia than in South Carolina?
No, says Jim Ray, a school superintendent in Spartanburg, S.C., who says his state's standards are tougher than Georgia's. The answer, he says, isn't for South Carolina to lower its standards but for the federal government to come up with uniform standards so all states can be judged equally.
"If you are not going to mandate a common playing field and a common measuring stick, then you don't really have any teeth in this system, except that you are going to punish the ones, ironically, that were trying to do the right thing," he told CBS News.
Grading No Child Left Behind: This CBS News and Time magazine video (4:51) looks at the successes and failures of the No Child Left Behind program while the federal government's role in education comes under review.