Basically, if you hear about a guy from early on, then he's likely a Plan A guy. If you were after a handful of guys at a certain position, and you didn't land any of them, and then all of a sudden a few new names pop up in the final month or so, then you know those guys are likely Plan B or C guys.
It's inexact, like anything else, but if you follow it, you can get a pretty good idea whether you're having to go to fall back plans or not. Another indicator is if you undersign, like we did in 2007. We missed on almost all of our top targets remaining on the board at the end of the 2007 class, and we had to back fill some even after signing day. It doesn't mean your fall back guys can't end up being good players, but I tend to think we had a better year when we aren't hearing new names late in the game.
ETA: I'll give you the example of Joel Kight. He was not highly rated, but we were after him early and often, and our staff made it clear that they liked him even though he was undersized. He had a couple other good offers, but our staff's interest is the main reason I was happy we landed the guy, and he obviously has turned out to be a player. To give you an example on the opposite end of the spectrum, we landed Cedric Smith, a CB from Alabama at the end of this past signing class. He wasn't on our list until the very end, and he only popped up after we missed out on another player, Dequan Menzie, at his position. Yancy tried to pump up that signing by saying the staff thinks he's a steal, etc., but I'm not buying it. He was a fall back, whether they think he has a shot to contribute or not.