> Thanks for the very thoughtful response! I admit I also get salty, particularly when it comes to education. It feels so obvious things should be a specific way, but of course that may just be my STEM person arrogance :P.

Thank you (also for indulging)! As an also-arrogant STEM person myself we can muddle through together haha.

> So, what I'm mostly confused about is why expulsion wouldn't work.

I think a number of dynamics are at play here:

- Schools don't usually reach for suspension/expulsion that quickly because they're weighing the impact of the problem kid's behavior on others vs. the impact of a suspension/expulsion on the kid, so their disruptive lingers.

- Some schools have zero tolerance policies that suspend/expel very quickly, but it turns out that creates a super weird climate (students defending themselves are also suspended/expelled, school staff feel pretty bad suspending/expelling all the time, you can't build relationships with problem kids which is deeply dehumanizing on both sides, etc.)

- Problem kids have a weird habit of just coming right back. A lot of us are envisioning a relatively rich school district with multiple nets to cordon off problem kids, bost districts have the one school, maybe if they're lucky there's an "alternative school" in the parking lot, which is a trailer that should only ever have 5 people in it, but it has 15. Maybe some people are advocating for some kind of super harsh zero-tolerance-expelled-forever pipeline, but let me introduce those advocates to the School-to-Prison Pipeline [0].

- Problem kids are still in your neighborhood, your kid is pretty likely to still see them outside of school, and that leads to more weird social dynamics.

But moreover, let's say that zero-tolerance-expel-immediately leads to better outcomes for kids and we have some way of totally segregating problem kids both in school and broader society. Those kids are still a problem for society that we'll have to deal with at some point. Today they're throwing stuff in class, tomorrow they're breaking the windows of your car or running drugs in your neighborhood. At that point in the School-to-Prison Pipeline, rehabilitating the person is extremely expensive.

> seems to be a clear-cut case of Simpson's paradox

Nah, definitely not. A commonly cited paper [1] has a pretty good table breaking down the effects of various classroom properties on outcomes. Reading it, you'll immediately get a great look at why private/charter school outcomes are so much better: they work pretty hard to cherry-pick kids that lead to better outcomes, thus exacerbating the School-to-Prison Pipeline issue by putting more pressure on public schools. Anyway, there's so much on this topic you're gonna have to switch your argument to explaining a conspiracy in educational research:

Suspending Progress: Collateral Consequences of Exclusionary Punishment in Public Schools: https://sci-hub.st/https://doi.org/10.1177/0003122414556308

Effects of School-Wide Positive Behavioral Interventions and Supports on Child Behavior Problems: https://pmc.ncbi.nlm.nih.gov/articles/PMC3483890/

Teacher Support for Zero Tolerance Is Associated With Higher Suspension Rates and Lower Feelings of Safety: https://sci-hub.st/https://doi.org/10.1080/2372966X.2020.183...

Schoolwide positive behavioural interventions and supports and human rights: transforming our educational systems into levers for social justice: https://pmc.ncbi.nlm.nih.gov/articles/PMC9897741/

School-wide positive behavioral interventions and supports and students with extensive support needs: a scoping review: https://pmc.ncbi.nlm.nih.gov/articles/PMC9897773/

The Impact of Schoolwide Positive Behavioral Interventions and Supports on Bullying and Peer Rejection: https://jamanetwork.com/journals/jamapediatrics/fullarticle/...

> Stuff about blame

Blame essentially never works, and it's because people are the products of systems. You talk about Goodhart's Law; another dynamic is where we do things that feel good or confirm our understanding of the world despite poor outcomes. Harsh disciplinary policies are the poster child for this. I'm gonna assume here you're pretty naive to the criminal justice space (this is because anyone who knows anything about criminal justice understands blame essentially never works), so I strongly encourage you to interrogate your priors here and read up on deterrence, punishment, and so on.

> National placement test for each grade

This would really only measure socioeconomic status, like most (all?) standardized tests. You also get stuck in tracks, so if say your mom dies in 3rd grade, you do poorly on the test and get bumped down, you're probably bumped down forever. That's a bad outcome.

> Disruptive students get kicked to penitentiaries.

Not only are there completely valid reasons for students becoming disruptive (parental issues, injuries, mental health issues, etc), the expense of this is out of this world. Even in the cheapest state (Arkansas) spending-per-inmate is $23k/yr--the median is something like $60k. Your options here are dramatically increase taxes or create a truly horrific human rights disaster.

> The same people that write olympiad problems and run the summer camps are hired to create a new curriculum.

This doesn't work because different people learn in different ways. You need dedicated, educated, well-compensated, supported professionals applying state-of-the-art techniques and research to get the outcomes we want. Also when you talk about replacing Common Core with some new standard, you're still not escaping Goodhart's Law.

> Everyone is fired, and as many people as money there is are hired at $300–500k/yr (in total compensation) to teach [30 student classes].

30 student classes obviates any benefit you'd get from anything else. There are no systems with those class sizes that are achieving the outcomes we want. You also can't literally fire all teachers. The NEA or teacher tenure won't let you. Training and interviewing 2.333 million teachers (plus administrators) is a gargantuan undertaking. Who moves to the middle of nowhere in Arizona, or Mississippi? How will you find so many qualified people? That $15k/yr number you keep citing isn't all salary; we spend around $236b on ~4m teacher salaries, which yields ~600k teachers (at $400k/yr salary), so you still need to find $680b (which is more than the budget of Medicaid) for the remaining 1.7 million teachers. You also have to somehow survive the political fallout of firing hundreds of thousands of people, many of whom have families and various health issues.

[0]: https://en.wikipedia.org/wiki/School-to-prison_pipeline

[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC9159706/#T2