Yes, acceleration certainly isn't for everyone. But as you note, the book doesn't say it is. So there's no problem there that I can see.
"Unbiased" doesn't always mean "not taking a stand." The point of this book is to *analyze the evidence* and *make an argument* about whether acceleration is generally good for GT kids or generally bad, in terms of policy. Should acceleration be ruled out entirely, as many school systems argue that it should be?
The book makes it clear that acceleration is effective in a large number of cases, so ruling it out as a matter of policy is a bad idea. It should be an option to be explored when it seems appropriate for a particular child.
That's not bias. That's argumentative writing.
