I had TAKS in Texas, which were the simplest tests I ever took. We had those in High School junior year, yet they were easier than the EOC's (End of Course test) in Middle School and the first two years of High School in North Carolina. That isn't saying much, though, I know someone who passed one of the EOC tests by putting all C's down his answer sheet (the teacher was amazed he could bubble them in so quick as well), though that was the "testing" year of that EOC test, so it didn't really count. I passed the English TAKS (essay included) on my first week of school in Texas, not knowing what the duece a "TAKS" was, nor caring about the test at all and just throwing nothing together to make a ball of junk three-four sentence paragraph for an "essay." Apparently that is the standard that they taught us...the next year, after the test.
Those incidents, the varied school systems even in a district, and the ease of all the tests in general (yet so many fail them -.-;) make me not believe in standardized testing. Probably a few other factors I can't think of, yet my brain is dead.