A lot of the discussion here focuses on critical thinking development which is an interesting topic. Does compulsory testing or even compulsory education in general do children any service in that regard? Are critical thinking skills better developed when a kid's education is self-directed? I think these are all fair questions.

Personally, I'm a fan of self-directed learning but that doesn't mean I'm right. Still, it strikes me that teaching people to think critically is like teaching them to be happy or to love. It seems kind of difficult to quantify.