Since I'm surrounded by teachers, I'll point to this by Yglesias:
|Smaller classes can have positive effects, but the effect is much smaller than the impact of having effective teachers. In other words, if you have 100 kids it’s better to have four good teachers teach them in groups of 25 than to have four good teachers and one bad one teach them in groups of 20. And not only better, it’s also cheaper. And since it’s cheaper, you could use the money you saved by not hiring the fifth teacher to make sure you pay the four good teachers enough to keep them in the classroom.|
I'm pretty sure my wife is a good teacher, so if her school wants to pay her more, that's a policy I can get behind.