Anyone who has been to college knows that there are widely different standards when it comes to what quantifies “passing” in different school systems. If your roommate can barely write a coherent sentence, but claims to have passed every English class in high school, you know that his English classes were probably much easier to pass than the English classes you took in your high school education. It’s not that you were an A student and he was a D student—you both got Cs, but the standard for getting that C was obviously different between those two school systems.

A recent study, conducted across many different states, in relation to the introduction of Common Core math standards, revealed that across the United States, what qualifies as “passing” varies wildly. A student who starts out failing in New York could move to New Jersey and suddenly be considering passing. Basically, a score on an exam that is fine in one state would be considered failing in another and above average in another.

Right now, there is no standard for comparing different states to one another. When it comes to comparing New York to New Mexico, for example, there is no way to know if their success and failure rates are actually comparable, because there is no yardstick for determining whether or not those two states are measuring their students in the same way—until now. A test called the National Assessment of Educational Progress has been introduced in an attempt to measure proficiency across all states. It doesn’t actually rate the students of those states, it rates the standards themselves, against other states and against the standards set by the NAEP test.

Some of the results are more concerning than others. The study found that when it comes to testing fourth grade reading, the vast majority of states have a standard that is far below the NAEP standard, Georgia being the state with the lowest standards for its students. Fourth grade math, however, has less terrifying results, with only four states that fell below the NAEP’s basic standards and quite a few that are actually exceeding what the exam considers “basic passing.”

Eighth grade reading’s passing standards are better than fourth grade reading’s, but there are still quite a few states that do not meet what the NAEP test considers to be “basic mastery” of subjects. Eighth grade math is where things go awry for most states. Many of those who had aspirational standards for fourth grade passing requirements, dropped into the “basic mastery” category (which is perfectly fine), but many states also fell out of that strata an into the lower standard strata, meaning that standards had dropped in between the time students were tested in fourth grade and when they were tested in eighth grade.

For an example to demonstrate the necessity of this test, consider the following: in 2011, both Kentucky and Arizona reported that 71% of their students were either at or above proficiency for eighth grade reading. When these scores are converted into the NAEP metrics, however, it was found that only 28% of students in Arizona were at that level and only 36% of students in Kentucky. When using their own standards, both states looked like they were performing at the exact same, very high level. When using a more standardized measurement, however, it is easy to see that not only do fewer students meet the proficiency levels across the board, that the metrics used to measure proficiency simply do not work when crossing state lines.

Why do proficiency standards vary so widely in the US? It’s largely due to the No Child Left Behind Act, which would seriously punish school systems for having poor performance on state-issued standardized tests. Instead of taking those punishments, schools lowered their proficiency standards, so that students who would not have been considered proficient in the past suddenly would be considered proficient.

Now that the results of the first waves of NAEP testing are starting to be analyzed and reported, initiatives like Common Core are starting to spread, and the No Child Left Behind Act is being reevaluated overhauled, states have started to raise their proficiency standards. At the last exam, however, only New York had standards for proficiency that met the NAEP standards for both math and reading. The process is slow going. Neither parents nor students like to see the standards change, especially because it means that students who were once considered to be passing no longer will be.