Different states do it differently in regards to private schools. Kansas is exploring a multiplier that may be put into effect in 2022-23. Kansas's premise is every parochial school with start with a multiplier of 1.0 and can then either go up or stay the same based on three factors:
1) Geographic Population: If there is a public school in the same area that is sorted into Class 6A or 5A, then 0.30 will be added to the private school’s multiplier. If a private school is in the same area as a Class 4A or 3A public school, then 0.15 would be added to the private school’s multiplier. (Think Norfolk Catholic, Fremont Bergan, Hastings St. Cecilia, etc.......Class C/D schools in towns of 20,000+ that are home to Class A/B schools).
2) Number of state championships in all sports won over the previous five-year period. If that total is more than 10, then the private school would have 0.30 added to their multiplier. If that total is between five and nine, then 0.15 would be added.
3) Third factor is based on a private school's free and reduced lunch population. If that total figure is below 20 percent, then 0.15 would be added to the multiplier.
The proposal in Kansas does that that a school cannot move up more than one classification due to a multiplier, and cannot force a school playing 8-man football to move up to 11-man. There is also no appeals process.
A total of 21 states use a multiplier of some sort. Oregon and Colorado also use factors such as socio-economic status and success history.
An older article, but back in 2013/14 a look at how different states at the time treated multipliers.
Ohio's attempts to find a level playing field for public and private schools follows the path of many other states.
www.cleveland.com