Most private schools are pretty expensive, so I would bet that most school districts, spend less than the median private school. But that's not my claim. My claim was that most of the crappiest public school districts (CPS, DCPS, NYPS, LAUSD) spend more than it would cost to send the students to a competitive [to the district itself] private school.

CPS: Per-pupil cost, $14k. Archdiocese of chicago: $7k

NYPS: Per-pupil cost, $19k

DCPS: Per-pupil cost, $18k

LAUSD: Per-pupil cost, $15k (official, 7k, a rediculous number, but independent McKenna college researchers estimate 15k)

These costs don't include capital costs. An independent estimate including capital costs for LAUSD suggests $30k/pupil.