<p>My kids have attended "good" private and suburban public schools at various points in their education. And same with me, all those years earlier.</p>
<p>The main issue to me was tracking in the lower grades. The particular private schools were academically selective, beyond the degree to which the public schools tracked. Being in classes of more homogeneous (high) ability- and not being tied to state-imposed curricula- allowed the classes to proceed at a different rate, at a different level. One of the schools was truly wonderful. At the high school level the public schools tracked also, and at that point the educational advantages indeed narrowed. But there was still advantage to these private schools due to finer tracking and smaller classes. My kids reported that for a given class at the private school, vs. an equivalent "Honors" class at the public school, the private had more and better class discussion, more written papers, more books read.</p>
<p>A second benefit was social. My kids simply got along better with bright kids, so being surrounded by a higher proportion of them resulted in a better social situation for them. </p>
<p>I've looked at where the kids go to college at each of these particular schools; the top 3% of these public school kids are attending the same range of colleges as the top third to one-half of the private school kids did.</p>
<p>My guess is somewhat more than 3% of the public school kids had similar capabilities, so it would appear to me that the private school kids did better in aggregate. However in some cases economics may have influenced destinations of the public school kids.</p>
<p>As well, the private school kids were much more likely to be headed to the very top schools. But then they were also much more likely to be alumni kids.</p>
<p>There are some kids at the private schools who may have gotten into "worse", but still excellent, colleges than they believed they deserved because a particular college simply wasn't going to admit more than say 10 applicants from their private school, and they were #11. </p>
<p>Back in the day the private school near mine was like that, everyone thought they belonged at Harvard and Yale, but in the end disproportionate numbers wound up at Penn and Columbia (when neither was considered so great). But, the year I graduated from high school, the valedictorian at the local public school "only " wound up at Penn as well.</p>
<p>My daughters' private school personal friends are disproportionally attending very top colleges. Their public school friends are mostly going to very good , well respected colleges, with some overlap with the others, but overall not as "top". But maybe they aren't as educationally outstanding individuals, either; hard to say.</p>