State test scores administered for accountability purposes are regularly used to adjust instruction in nuanced ways. This is no accident--No Child Left Behind demanded that students' scores be returned quickly to teachers in order that this might be the case, and the idea of data-driven decision making continues as one way the promise of education reform might be realized. But what if test scores from state tests were never designed to support instruction? What if the methodologies supporting these tests were intended for a purpose that actually had little, if anything, to do with informing nuanced changes in the curriculum? Or worse, what if the design is such that instruction in anticipation of the test actually makes the results invalid? And what if it is done anyway, out of fear, frustration or a feeling that no other option existed? The result might be akin to what would happen if people studied for the eye test at the Department of Motor Vehicles. There would be lots of people passing the test, but there wouldn't be a clue whether they actually could see well enough to drive. That eye test only works when it can reference something meaningful beyond itself. When it refers only to itself, it should be obvious it tells nothing about the thing it was trying to measure, and interpretations that suggest otherwise are just plain wrong. In this article, the author contends that using the same standardized test for evaluating classroom instruction and for high-stakes school accountability is wildly misguided and inappropriate.