"From September until Christmas vacation, [Brookside] was like any school you would imagine. Then, once they got back from Christmas break, for the next nine weeks until testing began, it was a different animal. What they did was drop their curriculum, drop their texts, and instead study exclusively from a standardized-test prep book. Kids weren't getting a liberal arts education, but prepping to a very narrowly drawn standardized test in primarily language arts and math. Because they were interested in passing the test more than anything else, for that 22 percent of the school year, they taught primarily to the broad middle section of kids that were going to pass. Plus, the school went and reached out to those kids who they thought were on the cusp of possibly passing. So who gets left out? The kids at the bottom and the kids at the top." [0]

It's not the tests per se, but it's what is put on the line. Raises, funding, evaluations, keeping your job - these are all disincentives to well-rounded education. Please don't make me quote the plethora of studies that show how important arts, literature, and the sciences are to primary education. Completely stopping studying these things for half the school year is bad.

So it doesn't matter if the tests are filled with good-to-know knowledge - they're positioned to dis-incentivize and devalue anything that isn't math, language arts, and a narrow reading of how to structure an essay.

[0] http://www.usnews.com/opinion/articles/2013/04/11/why-excess...