Many people can learn to program and companies that pay poorly will only be able to hire people who aren't very good and they will go out of business. Finding good teachers is very hard as well but the government will only pay terrible salaries and mostly hire poor teachers. The difference is when the teachers suck and students do poorly, the school doesn't go out of business, they just reduce the budget and it gets worse.

>The difference is when the teachers suck and students do poorly, the school doesn't go out of business, they just reduce the budget and it gets worse.

This is true, but it's become a partisan issue, at least in the U.S, to talk about testing teachers in some way.

I believe a huge problem is finding a way to differentiate a good teacher from a bad teacher if you're not allowed to look at grades/some kind of standardized test. If you can take those into account, as long as a teacher comes into work on time I'm not sure how you could differentiate the good from bad.

An example I like to use is my AP Calc teacher from highschool, who had an average score of 4.7 for her students on the AP test. The average in 2012 was a 2.9 (the year I took it, it seems to be higher now, I can't say to as if they made it easier or if people got better though) [1]. In many school systems though, if your teacher has an average score below the national average, you can't do anything about it.

[1] https://www.totalregistration.net/AP-Exam-Registration-Servi...

Part of the problem with doing that, especially in younger grades, is that so much of it depends on variables outside of a teacher's control. A lot of reading at a young age comes from life experiences. For instance, someone who has never been outside of an inner city is going to have more trouble reading a story about someone sailing on the ocean because they are so far removed from even the most basic plot elements that the things in the story that are actually meant to challenge are not ever gotten to. Additionally, time spent outside of classroom compounds the effectiveness of time spent inside of classroom, but the teacher has no control over that. A teacher can't even control if a student shows up for school or not. Student's performance, especially cross-school comparisons, are nearly worthless and would unfairly punish those that teach at low schools.

I would say you'd have to compare them to similar schools in the area or similar areas in the U.S. Between income range in the surround neighborhoods and population density you should be able to come up with a decent comparison, I would think.