I'd be happy to participate in a poll like the one suggested, though I honestly think it would be better approached as a study.
My eldest skipped two grades and started a dual enrollment high school/college program at 14. My youngest started first grade almost exactly on her 5th birthday, making her young for the class behind her (another girl her age is two years behind DD because that girl is a few days on the far side of the birthdate deadline, whereas my DD is a few days inside it).
Here's the thing (well, two things really), and I suspect this opinion won't be popular. When kids get into higher grades, the executive function demands increase over what they were in primary school. They increase again in high school, and in college, they're very high. Also, physical development is an issue, especially for kids who are small and/or 2+ years skipped.
There have been many discussions on this board about asynchronous development, and most people here are familiar with the idea that executive function (EF) doesn't always (or even usually) develop at the same pace as other cognitive functions. This reality can leave a grade-skipped young teenager in a very difficult position, especially because many educators don't know much about EF.
Kids around 12-15 are highly vulnerable to the seduction of distractions like computer games, hobbies, and what-have-you. If they're in an environment that demands a lot from them, they're at risk for, shall we say, underachievement relative to potential. Combine this problem with relatively immature executive function, and problems can happen. These problems are real, and they can be very damaging.
Compound the EF dilemma with being a lot younger than everyone else, and the problems can get worse. Young teenagers may be more susceptible to pressure to fit in with older kids in their classes who may not be the best role models around. Younger kids are typically a lot smaller than their grade peers, and when puberty comes around, a child who's been accelerated by 2+ years will be a prepubescent in a class of kids who are 6-8 inches taller (including the girls) and who've spent some time thinking about things that have not really entered the mind of the younger kid. The younger kid won't fit in with his or her classmates for ~2+ years (starting in 8th for boys, younger for girls), and there really isn't anything you can do about it.
The physical thing was really, really hard on my eldest, and he struggles with good study habits. My youngest will start 7th grade just before her 11th birthday. She's very tall and is basically the same size as her classmates, but the executive function difference is real and obvious.
Personally, from where I'm sitting and from what I've seen, one grade skip is less of a big deal for most people in these two regards. I've spoken to adults who regretted single skips, but they were in the minority. I've spoken to adults who skipped multiple grades, and most weren't happy about it at all. Here's a sample of the stuff I've heard: Try finding a date for the dance when all the girls have deeper voices than you do and I was miserable in high school because I was so different. All they saw was my IQ. That kind of thing.
My daughter struggles with being so young. There's an element to it that's exciting and an element that's scary. This is a girl who's outgoing, independent, and open to trying whatever new thing comes along. My eldest son has always been good at adapting to a new situation, which both helps and hinders him. Sure, he can fit in with kids two years older than him, but at the same time, I'm not sure he likes all the you're-so-smart comments, and I don't want him to feel like he has to live up to them. It's also hard for him to find a study buddy when the other students in his science or math classes are 4-5 years older than him.
I know that people get very excited about grade skips, but in my experience and from what I've learned in informal interviews over the last 8 years or so, it's a mixed bag that can come with problems that are as serious as the ones you're trying to avoid. Yes, the school system is a huge part of the problem, but the school system is what it is right now, and I think it's important for parents to be aware of the downside of skips. I read a lot about the positive side of skips (and yes, there are many positives), but way down the road, negatives can creep in.
Overall, right now one skip is working best. We wouldn't do another one for our DD. I'm honestly not sure what to think about the second skip our eldest did. Intellectually, it was right. Otherwise, I'm not so sure.
I know that YMMV, but I suspect that people get carried away with enthusiasm for grade skips without listening to the very real negative sides.
