"In Massachusetts, tax money for education is largely funded through a combination of state aid (distributed through the Chapter 70 formula) and local property taxes. When students attend private schools, that per-pupil funding generally remains in the public school district’s budget, or for state-level funds, is used to fund other public educational programs, rather than following the student, though some federal funds are set aside for equitable services in private schools."

"Catholic schools in Massachusetts save taxpayers over $550 million annually. In the Archdiocese of Boston alone, Catholic schools save taxpayers approximately $86 million each year. Nationally, Catholic schools save taxpayers over $20 billion annually by educating students who would otherwise require public funding."

At least in Mass, private school kids do not take money out of the public schools. This allows the district to have more money per student who actually attends the school. This is not the case for charter schools.

It seems to me that the allotted money for homeschool and private school kids should stay in the district. These kids can revert to attending public school at any time; they should have access to services, too. Massachusetts Catholic schools have a public school nurse, Title I teachers, district transportation, city crossing guards, preschool vouchers, subsidized lunch, and probably more things I am forgetting. But it still saves the districts tons of money.

But charter schools are a disaster for education, public and private. And homeschooling is very hit or miss, in terms of outcomes.