Sometimes to get a handle on who is doing something wrong you need to see how many are doing it.
For example, suppose that Jack, Jill, Bill, Belinda, Melinda, Mark, Lark, and Larry are going on a hiking trip, and Larry is always much slower than everyone else. He's holding the whole group back, because everyone has to stop to wait for him. On top of that he's whiny and seems ill-prepared. You would conclude that Larry is a problem. He needs to be talked to, to fix up his behavior. Maybe he doesn't really belong in this group, maybe he should never have gone hiking to being with. All reasonable. Your steps to deal with this problem would be to try and change Larry's behavior or his dependence on the group in some way.