Spend per pupil is a factor, but I have to agree with the parent poster, if you remove bad, disruptive, or underperforming kids from a school, and replaced them with disciplined, over-achieving students, the rest of the student body benefits. This is independent of school funding.

Private schools, even ones that receive less tuition per student than public schools of the same district prove this point because they can set a higher bar and more readily kick out disruptive students.

California spends more money on low-income school districts than the average, and I think that's generally true most other places, especially since No Child Left behind (which for all it's problems by-and-large forced states to invest in poorer schools.)

Nationally, per student cost at Catholic parochial schools is roughly 1/2 of public schools. (Couldn't find California specific numbers, but it tracks what I've seen.) That's cost/spending; tuition is even less. Special education programs eat up 1/4-1/3 of public school budgets, so there's still a gap after accounting for that.

1973 was over 50 years ago. Even the poorest, most "backward" states have long ago largely remediated spending inequities. What you hear today to support claims of inequity are cherry-picked esoteric cases to drive outrage, just like every other topic today. In reality there's clearly much more going on than what advocates for this or that would ever admit.

Private schools get to pick their customers. Public schools have to take everyone.

That's true to an extent, but much less true of Catholic parochial schools. In fact, such schools will sometimes have a population with average income less than the local public schools. Of course most parochial schools won't have special education programs, so that's a huge filter, but as I pointed out doesn't account for the budget gap.

In any event, "picking your customers" is exactly the point of the previous poster(s). Money doesn't really explain what we're seeing. Once upon a time there was a very strong correlation, and people presumed causation, but now it's quite clear that the causation wasn't there. Certainly not directly, which is why throwing more money at the schools isn't helping.

Money can be extremely strongly correlated but if I get to kick out the bottom 20% of shitheads I can still outperform you on half the budget. Not talking income wise, talking behavior wise.

Sounds similar to charter schools in NYC. They often get better results than public schools but because they “manage out” kids with bad behavior and/or learning disabilities, in a way public schools cannot.

Some public charter schools do the exact opposite, take in the problem kids so they can be given an environment better suited to their challenges. For example, Gateway Highschool in San Francisco. And they have better outcomes for those kids. But better is relative, and they get alot of criticism from those convinced equity demands the whole student population be perfectly shuffled across all classrooms, and who argue having such options excuses the district from providing even more resources to the average classroom. Many of those same people also work to prohibit ever removing a problem child from a classroom (see recent controversy in SF, about schools secretly doing that despite city prohibitions on suspension or even class removal), arguing instead every classroom should have 2 or 3 additional instructors, as if that would magically cease the disruptions.

It's doubtful that a catholic parochial school has ever turned away a catholic student. Certainly if that happens, it must be rare. If catholic students are superior to non-catholics, through some self-selection process, how does that invalidate his point? They're not being picky intentionally. A great many admit non-catholic students, often on scholarship, those students also tend to do well.

Public schools have to take children that do not want to be there and make it everyone's problem, and their classmates suffer for it. Maybe this public school policy is the issue that should concern you.

I would imagine that catholic parochial schools are selecting for parents that bother to put in the effort to swap their kids from the default, free public schools to the catholic schools.

That is entirely my point. Catholic schools aren’t doing anything special they are just not keeping the problem kids. Why do you assume this doesn’t concern me?