The selection bias of SA pales in comparison both purely by principle and in practice by the diversity of it's students.
And who care enough to move (showing a massive parental interest in their child's education).
This is why using test scores to compare schools, be it charter vs. public in the same district or public vs. public in another district, is inherently flawed.
With zoned schools you can have an interest in your childs education and have no way of getting in simply because you can't afford it.
The point is that those who claim that charter schools get to pick the good students and leave the bad ones with the public schools are simply wrong. It's the public schools in the rich areas that get to pick their students simply by whether they can afford to live where they do or not.
no, they aren't. Sorry, this isn't a matter of opinion, it's a matter of fact. Every study ever performed on this question indicates that you are the one who is wrong.
> It's the public schools in the rich areas that get to pick their students simply by whether they can afford to live where they do or not.
The existence of selection bias X doesn't preclude the existence of another selection bias Y... why would you think that's the case?
That being said, I'm not sure either of these are a problem. The real problem (one of them at least) is that a school's performance is measured by the student's scores on standardized testing.