I don't usually do this, but I just hammered out a large post. I'm now to attempt a short version. If you find it intriguing, follow the link to the long version.
Some reformsters keep trying to shore up teacher evaluation systems by referring to the private sector where, we are told, folks are rewarded for doing a good job and suffer for doing poorly. Why, they ask, should teaching not come with a performance based incentive system?
I believe that's a false comparison. A really false comparison.
Teachers are not private sector employees. They are public servants, and public service does not play well with performance incentives.
Nobody proposes that we make performance incentives for police officers that reward them for higher numbers of arrests.
Nobody proposes that we create fire fighter performance incentives based on the total dollar amount of property they save in a month.
Nobody proposes that mail delivery persons be rewarded for delivering to a certain number of addresses per hour (if you can't see why not, think about Montana instead of New York City).
Nobody proposes that we give national guardsmen bonuses based on the income of the people whose property they protect.
Nobody proposes these things because public service means serving the whole public, all of them, equally, without prejudice, without ignoring a part of the public because it might hurt your numbers or screw up your monthly performance bonus.
I stretch it out and fill in the gaps in the longer post, but that's the nut of it.