ever since then players have,...,suffered more concussions.

[akhils188]

Hi, is this an independent clause? Ever since then players have, somewhat paradoxically, suffered more concussions. If it is, how can you say it's independent. I thought it is a dependent clause because there is some doubt ever since what? this is from q5 chapter 3 sc manhattan verbal guides.

[Sage Pearce-Higgins]

Yes, this is an independent clause. Sure, I agree that we'd need a bit more information to make complete sense of this sentence (like knowing what time's being referred to), but grammatically speaking, it's a complete sentence.