[verall]

I say this every time that education unions are blamed, but there are many states which do not allow teachers to collectively bargain in any way, thereby completely defanging the "unions" which exist in those states, and yet students in those states have lower test scores and educational outcomes on average.

There is already a live experiment where education unions are totally neutered, and it didn't fix anything. Private schools "work" because they get to expel anyone who doesn't pay enough money to outbalance any problems they cause. Public schools obviously cannot do this.

[zaphar]

I did not only blame the unions for the current state of things. I merely stated that they stand in the way of one of the potential solutions to the current problem. I don't find the debate of whether there is a hypothetical world where giving them more power would help the state of our schools particularly interesting or compelling.

    Private schools "work" because they get to expel anyone who doesn't pay enough money to outbalance any problems they cause. Public schools obviously cannot do this.

This is an interesting statement that tries to attribute a private schools success to a single cause. I find this unlikely in an area where there number of confounding variables is so high. I also don't see why I should take the cause as true. But let's put all of that aside for a moment and ask the entirely reasonable question: "Why exactly can't the public school expel problem students?" If as you say it's the secret to a private schools success maybe public schools should think about copying it.

[verall]

> "Why exactly can't the public school expel problem students?" If as you say it's the secret to a private schools success maybe public schools should think about copying it.

Because the main purpose of the public school system isn't to provide the best education for the most capable, it's to provide an acceptable education for the average student to eventually work a basic labor job, to provide daycare for working class parents, and to keep teenagers mostly busy so that they commit less crimes.

Expelling every problem student would totally fail at these goals, and would create an underclass of problem teenagers who have mostly nothing to do but commit crimes and get eachother pregnant. This would be a massive failure and much more expensive than public school. It would worsen the lives of the millions who would have otherwise grown out of these negative tendencies.

Further, it's not the only secret to private schools success, only one reason. Other reasons are costing money and therefore disqualifying poor people, parents who pay money for their children's school are more likely to be invested and involved in their child's education, and private school teachers are paid much more money than public school teachers. All of these factors contribute. I just listed a one, since the only reason you listed was unions.

A more interesting comparison is between public schools and charter schools which are not allowed to use selective admissions (must admit by lottery etc.), which is much closer to the public school system. My understanding is that they do a little bit better on average at the cost of more outliers. And even they avoid the most checked-out parents who couldn't be bothered or are actively hostile to filling a free application for a school.

Oh - and you said you didn't only blame unions, but the only other targets in your post are teachers and administrators, which private schools also have. Can you expand on this?