Jeff at So You Want to be a Science Teacher does an excellent job of responding to ReformK12’s claim that a Colorado plan to provide vouchers for special education students would not siphon off students with mild disabilities leaving behind those students with the greatest (and most expensive) needs in the public schools. Jeff’s research found a similar plan at work in Florida that did indeed leave the students with the greatest needs behind.
When I posted my voucher questions last week I neglected the fact that the voucher amount given students to take to private schools is usually the average cost per student. As Jeff points out, in most systems, the cost of educating a child with some kind of disability is higher, sometimes much higher. Another factor at play here are several federal laws which require public schools to provide extra "accommodations" outside of the classroom for many special education students (also underfunded by Congress, incidentally). I doubt many private schools would be willing to subsidize these extras and those schools that specialize in working with students with disabilities often have higher tuition, sometimes much higher, than a typical voucher amount.