Now some may argue "it's good to have high standards; good for the college board!" however there's a problem with that statement. Think about the purpose of an exam: to measure student content knowledge. By making a dramatic shift in a single year, the College Board has either proven that a) the test was way too easy for decades or b) they intentionally made it more difficult this year "just because". Why is this true? Because the content didn't change. There weren't suddenly tons of new chemistry concepts introduced into the world two years ago which has caused all these changes. Chemistry is still chemistry, ions are still ions, and chemical equations still balance the same way. The laws of the universe haven't shifted recently, nor has Inception inspired any new changes to our understanding of space/time. If the content is the same, and the students (in large numbers) are the same...then lower scores on a new test indicates that the test was designed to have lower scores.
Now, I don't teach chemistry, so this makes little difference in my life, however the concept carries over into all subjects, especially those with any sort of standardized testing. In fact, any standardized test, given over time to large numbers of students will have an intentional distribution. In other words, the test results aren't random; they're predesigned. If 75% of students pass the Keystone, a district might be excited about their scores, but in reality, the test was created to hit that mark. Of course this also means standardized tests, required for graduation in the state of Pennsylvania, are designed to fail certain numbers of students each year. The students now must take remediation courses and retake the test...both which make money for the testing companies. Nice work if you can get it.
Some people ask me if I ever worry about standardized tests; the short answer is no. The results have already been predetermined, over a large sample size, based on the difficulty level set by the testing companies. Even if we somehow got every single student in the country to pass in a given year, they'd simply raise the difficulty level in the following year to "adjust" the distribution. Conspiracy theory? Nothing so dramatic...it's just business. Sadly, the students are the ones that pay.