The buzz word is "accountability." Why are teachers special? Why don't they feel they need to be evaluated like other professionals? Why do they feel they need a "job for life?"
Of course, the job for life line is nonsense -- teachers have tenure, but that's just due process - not a guarantee of a job.
Friends in the private sector ask "if a teacher is doing a good job, why do they need tenure? In the private sector as long as you're producing, you've got nothing to worry about."
Well, first I dispute that last sentence. second, K-12 education isn't the real world. It's rife with stories of administrators that go after teachers for no apparent reason. Why? Because accountability doesn't mean accountability - it means we can fire teachers at will. No one wants accountability to apply to anyone except the ground troops. I don't have an exact attribution, but Mayor Bloomberg is frequently quoted as stating "If parent's don't like the way I run the schools, they can boo me at parades."
Beyond that, the powers that be state that teacher accountability revolves around flawed "value added" metrics but other bloggers such as Gary Rubintein have already done a great job debunking that.
The solution is to simplify. There's a better way. Let's start by making the principals accountable. Bottom line is that they're responsible for a school's success. If the school doesn't cut the mustard, then they're out. But, how do we measure this?