This is one thing that bothers me with hosiery sizing. It's difficult to determine if a size chart is "spot on" or if the sizing runs smaller or larger. There are some department store retail sites like Macy's and Bloomingdales in the USA that add this "size factor" in reviews. And so you can see if there's a trend reported. But it's time consuming to track down and there's not always people making an effort to fill out this info. I wish a hosiery specialist out there having access to most of the major brands would make a sizing evaulation.
I know this can also be difficult to construe by brand, as some lines might run differently from others within the same brand. And maybe even by size. For example, size S and M may come up as "true to size" but L and XL may come up as "runs larger".
Anyway, I don't know if this kind of topic has been brought up before, but I was thinking if not, maybe members here with a lot of brand experience could weigh in.