Douglas County schools says spring survey inconclusive - The Denver Post

I realize there are political forces at work, but the idea that 4,900 survey responses out of 76,500 possible isn't "statistically valid" because it falls short of a 30% response rate is laughable. That's the funny thing about samples: they really don't care how big your population is. Now, if DougCo wanted to argue that the 4,900 responses represent a large but biased sample, that'd be a different story.