And, statistically, homeschooled kids tend to outperform kids educated in public schools and even sometimes private schools. So, homeschooling parents must be doing something right.
They're apparently doing a lot right. Hiatt's point about parsing data has some validity and the base selection bias of home schoolers being generally more invested in the value of education is noteworthy; nonetheless, the performance disparities (on average) between public and home schooled are impressive and persist (in a a number of analyses) when demographic and socioeconomic disparities are considered. (I was not home schooled btw.)
Average SAT scores for the home schooled has consistently been nearly 100 pts higher than public schooled going back to at least 1999 per a Dept of Education study, and the gap has been gradually increasing (84pt diff in initial report).
They also outscore on the ACT test.
According to Scripps, home schooled are overrepresented by roughly 5x among spelling bee finalists, a disparity that's persisted since at least 2001.
An analysis pub'd in the Journal of College Admission concluded homeschoolers earn higher first-year and fourth-year GPAs in college even when controlling for demographics and other factors.
Home schooled college graduation rates are nearly 10% higher than public schooled (66.7% vs 57.5% for 2022 roughly reflecting the norm for the last couple decades)
A great deal of the performance difference is probably due to home schooling being more focused on actual education (rather than subverting with ideology) than public schools. And, of course, not having to cater to the lowest common denominator in the curricula.