I might be wrong, but based on my understanding is that PISA also covers private schools, although that may only apply outside the US perhaps? I say this becaus

I might be wrong, but based on my understanding is that PISA also covers private schools, although that may only apply outside the US perhaps? I say this because many studies that compare US public vs private education student populations will sometimes cite differences in PISA scores. Students who are home schooled are excluded, but that population (even in the US) is far too small to move the average (It peaked at 5.22% during the pandemic I believe)