Well, let me see. I can't see "idled" hubs there for one...yet we have a short time to correct any problem with that time of issue prior to being dropped from Google search.
We can not see broken links, which will pull a hub down in search rankings.
Wait a minute, I could go on, but I should not waste my time answering this, lol. Any seasoned Hubber could come up with a list.
Edit: Ahhh...only been here three months, eh? Well, as you are here longer, you will get more familiar with things, lol.
Btw, I was using Google Analytics when it was a new born child, so I am very familiar with it.