> I find it hard to believe great teachers would go to private schools in large numbers as a result of being in a union, private schools generally have lower pay, lower benefits, and lower standards.

I don't know where you lived, but this is the opposite of the situation in most places. Private schools attract people who will pay private school tuition because they offer higher standards.

In my limited experience with private schools, it was relatively easy to poach good teachers away from unionized jobs precisely because the school had freedom to offer them higher wages and better benefits. Many of them were also sick of dealing with the issues that come with unionized labor and union membership.

In 2011-2012, the average pay for a full-time public school teacher was $56,410. For a private school teacher, it was $40,200.

https://nces.ed.gov/programs/digest/d13/tables/dt13_211.10.a...

It might not be accurate since many religious institutions have schools where nuns, monks, priests, etc work as teachers. They often times do not get paid or make basically minimum wage. Do you have any numbers that take that into account?

They have higher standards for decorum and appearance, but not higher academic standards. One of the advantages of private schools is that they are essentially exempt from standards. Their students are generally not required to take standardized tests, and the schools generally are not required to follow prescribed curricula. I agree that private schools generally have a higher standard of cleanliness and facility upkeep. And although the families have to pay more for students to attend compared to (free) public schools, teachers as a broad class are paid less, not more, at private schools. There are numerous reasons for this. For one, a prospective employee has even less leverage than they do when seeking employment at a public school.