Private vs. public school comparison introduces a lot of compounding variables including skirting the requirement to adhere to the same teaching standards - a lot of private schools embed either religious or political ideologies into their teaching which drives private interest groups who share those interests to financially underwrite them.

Sadly due to how strange private education in the US can be I don't think any comparisons between private and public education are really fair.

That seems like an incredibly misleading comparison at best. There are about a million other variables factoring into that, obviously including the money spent per kid, and the background of the people attending the school.