I'm not following the projections on how charter schools might supposedly impact the public schools or special education in remaining public schools.
I am a governing board member for a charter school. I'm not the most versed in education finance because I haven't gone through that training yet, but I can see some flaws in logic as compared to what I know.
A charter school functions within a district. The district provides support services, things like insurance, legal review of contracts, personnel advice, payroll, interpretation of confusing educational laws to ensure compliance, technology support, etc. The district receives payment for these services. In my experience, the district receives X amount of state dollars per in-district student, and the charter school receives a contracted amount of it.
Every student received the same amount of funding, however extra money for Title 1 is received through grants. It's separate from the amount per student the district receives form the state.
Students transfer in and out between charter and public all the time, it's a wash as far as funding.
As far as charter schools growing, virtual charter schools have the capacity. They need a teacher or a learning guide per X number of students. When open enrollment periods end, the school knows how many staff to hire for the coming year.
If there was a mass exodus, in my state, schools would have a major problem the first year because teacher contracts are renewed unless they get written notice - which is due before the open enrollment period ends. If a school had more teachers under contract than they had enrolled students, there would be a big problem. It would be hard for charters to staff to meet the needs of larger enrollment too when teachers are under contract to teach elsewhere (although many virtual charter teachers are also fulltime bricks&mortar teachers)
