Can't speak for the rest of the world, but my 8th grade daughter threatened to throw her iReady math test because she's tired of being tested when the tests don't affect her grades. My kids are over tested to the point that from their perspective the schools care more about testing than learning.
This seems unfairly downvoted as a sincere question.
The answer is that the types of standardized tests that these country-wide statistics are based on are not, in the US at least, the tests that generate your grades or your university admission.