The unions don't want mediocre teachers to be found out. It's really a crappy situation and really took us by surprise.
In the wartime Marine Corps he wasn't promoted quickly but he was still given the duties and responsibilities he was capable of as soon as he proved himself.
The private armies and so forth were mostly a 19th century phenomenon.
Sadly, this appears to be true in many walks of life.
I don't have any concrete facts on why unionized teachers are better, but they're paid more, have better benefits, legal protections... so maybe that makes them more motivated.
Also, rather than holding teachers to a standard "all students must perform as well as X", we can measure value added. Come up with a statistical predictor of how well a student will do. Then measure actual performance and evaluate teachers by (actual performance - predicted performance), averaged over all students.
I have no love for unions in general, especially those I've had the misfortune of dealing with in the tech sector. I do however appreciate some of what the teachers union my wife is a member of provides. All teachers in our state (and most others) are required to purchase and hold liability insurance at all times. The union has negotiated rates that are over 50% less than individual rates offered by these same insurers. The union has legal representatives available to protect teachers from many different types of actions, this includes the very real threat of false accusations made by students or their parents. The school districts don't provide any of those services, and in some cases are legally prohibited from doing so as teachers are state/county employees so they fall under various laws that limit the benefits that can be offered to state workers. Teachers unions also provide representatives to mediate disputes between fellow teachers, administrators, parents, and district staff. This service can be invaluable, especially when mediating disputes between staff members and principles. Having a run in with a principle can ruin a teachers career due to the nature of how many administrations work and the good old boy system at work during hiring at many schools.
While teachers unions do use collective bargaining to negotiate contracts which include salary schedules this only has a minimum effect on most teachers. Some stellar teachers don't make as much as they might, and some mediocre teachers make more than they should. The problem is that even without the teachers union state laws often limit compensation that can be offered anyway, and at least in my state, compensation packages are done in groups or packages regardless of whether or not those workers are unionized. This means that superstar teachers wouldn't be able to get higher salaries than they do now anyway. Given that almost all state workers here are payed based on time on the job and job classification there would be very little difference. It could actually be worse given that teachers currently get more money based on their continued education in addition to years of service. This provides incentive to teachers to continue to learn and, in theory, become better teachers.
As for mediocre teachers being defended by the union, that's an unfortunate consequence of what the union offers. There are several well publicized cases of horrible or mediocre teachers being protected zealously by out of control unions or union reps. Given the total number of teachers employed, the total number of cases the unions mediate, these are the exception and not the rule. You aren't going to read about a teacher being protected by a false student accusation unless it actually goes to court. As a member of the union if there is any type of a dispute you have the right to call on the union to defend you. In most cases this is still a problem with the mediocre teacher and not the union directly. By paying those union dues the teacher gets the right to have the union step in on their behalf. In some cases you'll notice that there's a problem with public service in general. The teachers union has negotiated for contracts and rules that are unbelievable, so have the police, tech and other unions. For whatever reason people love to single out teachers unions and teachers in general.
My experience since my wife has become a teacher and I've become much more aware of what goes on at schools is that most people arguing for changes in schools have no idea what they are talking about. They have not volunteered at schools, they have not actively participated in school board meetings, they have never seen a teachers contract, they don't understand the laws that are already in place, they don't read the legislation that's pending on the state or federal level, and they don't think about or understand the consequences of the legislation they do read. There's a lot of that in the discussions about education on HN too as well.
One example given was of a 17-year teaching veteran- an English teacher that was illiterate! I'm not entirely sure how that happens, but anything is better than what is currently happening with our schooling system- and make no mistake, it's not an education system, but a schooling system as former NYState educator of the year John Taylor Gatto [2] argues [3-5].
[1] http://www.thecartelmovie.com/
[2] http://www.johntaylorgatto.com/
[3] http://www.amazon.com/Dumbing-Down-Curriculum-Compulsory-Sch...
[4] http://www.amazon.com/Weapons-Mass-Instruction-Schoolteacher...
I am considering a startup in this space myself.
And you will make teachers teach to your performance criteria.
Besides how many programmers would like their value to be assessed by a piece of software?
I would assume you'd analyze based on the first and second derivatives of the students' results—good teachers leave kids better off than when they started, and great teachers teach kids how to learn faster and better. The important prerequisite to this, though, would be to test kids both before and after each lesson, with tests of equivalent questions and equal difficulty—otherwise, you have no idea how much of their learning was because of the class, and how much they already knew.
Rather than the current No Child Left Behind policy of regression to the mean, this would assign the most "learning-intensive" teachers to the students most in need of learning, and assign the students who self-study or are otherwise pre-informed to teachers who are more "lenient", likely diving further into interesting sidebars and tangents. Both groups would be better off for it.
The only way I can see to game derefr's system is to pack your class with students who used to have bad family situations, but who's family situations have recently improved. I rather doubt there are enough students in that situation to pack many classes.
You could normalize data to get relative values across teachers and classes. The intent was to find individual students or classes that needed more resources or attention. It was never to get people fired, but the unions fear that's how it will be used.
If I knew the criteria, I wouldn't mind, because then I could game the system.
https://docs.google.com/viewer?url=http://econ.ucsd.edu/~kam...
I think most programmers would be very happy if their performance was assessed by software, e.g. get paid for making unit tests pass. That's the holy grail of consulting: you get a spec, you build it, you get paid, no last minute changes or "this isn't what I meant".