Unlike many of my colleagues and friends, I personally support the use of standardized testing results in education policy, even, with caution and in a limited role, in high-stakes decisions. That said, I also think that the focus on test scores has gone way too far and their use is being implemented unwisely, in many cases to a degree at which I believe the policies will not only fail to generate improvement, but may even risk harm.
In addition, of course, tests have a very productive low-stakes role to play on the ground – for example, when teachers and administrators use the results for diagnosis and to inform instruction.
Frankly, I would be a lot more comfortable with the role of testing data – whether in policy, on the ground, or in our public discourse – but for the relentless flow of misinterpretation from both supporters and opponents. In my experience (which I acknowledge may not be representative of reality), by far the most common mistake is the conflation of student and school performance, as measured by testing results.