<p>I think a lot of this question has to do with the grading system the school uses–how they convert your GPA from the out-of-100 scale into the 4.0-scale seems to be a big mystery. I mean, I’m taking the most rigorous course load in my high school–which, while extremely difficult to balance, does not look as impressive as the students from other schools who take 10 APs and such (rigor varying from school to school is a whole other topic 
)–and I had a 98.1/100 GPA (UW) when it was last calculated (it’s probably down a couple of points by now, senior year has been the hardest yet). My guidance counselor says that that translates into roughly a 4.3 UW, and ~4.7ish weighted, but I have no idea how you get from 98 to 4.3. </p>
<p>As to the OP’s query about public schools–well, obviously I’m biased, since I go to a public school, but here’s my take on it: I’m in three AP classes this year (my school’s AP offerings, though the classes themselves are great, are in short supply), and I probably work on homework for 4 hours a night and at least that amount of time on the weekends. So, achieving my 4.3 or whatever is not easy at all, which is probably why I’m valedictorian of my class (last time I checked…): there are only a few other people in my graduating class who have that kind of average. Maybe my school IS public, but it’s also difficult (people do extremely well on AP exams–to follow the AP Calc example, about 70% of the Calc class every year gets a 5, and very few people fail it). </p>
<p>If, however, I went to private school, I’d like to flatter myself that I’d be able to keep up a similar difficultly level in classes…but I’m also sure that my grades probably wouldn’t be quite so high, if only because the frames of reference people have regarding GPAs are different, as you were describing above: perhaps more of a collegiate system than a high school everything-out-of-100 mentality. That most certainly does not mean, though, that public school students are cruising through doing comparatively little work for exorbitantly high grades. I sweat for every one of those points. </p>
<p>Looking at the issue in the context of college admissions, though–does it really matter? As a student at a public high school that is largely unknown to admissions officers (so few people apply to ultra-selective schools, like Midd), I’m assuming that my GPA will work in my favor, since it’s a testament to how hard I’ve worked in my public school setting (especially when corroborated with my SAT and AP scores). Whereas, though a student at a tough private school might not have the kind of GPA I do, colleges will recognize the GPA he/she does have in the context of their private school experience. So I’ve got the pure numbers, Private School Student X has the awe factor that they achieved their (lower) GPA at a private school. </p>
<p>This is just my perspective–I know of other public schools in my area where supposedly an A in something there is roughly equivalent to a C at my school. And plus, I’m biased because I’d rather not think that I’m not getting held up to rigorous standards or that I’m the lesser student because I don’t attend private school. </p>
<p>Oh, and one other thing (wow, sorry this is so long!): just remember–CC is CC, and the people on here seem to generally be representative of a small minority of extremely motivated students–just because you see tons of CCers with over 4.0 GPAs doesn’t make it a common occurrence in public school! :)</p>