This is a pretty ridiculous topic but seeing teams get a 3rd or 4th round compensatory pick got me thinking.  That's a nice bonus.  Anyways, the NFL does not release it's formula but this article below seems to do a pretty good job predicting it.  It's pretty much what you would expect, value of players received vs. value of players leaving (based on salary and playing time on the new team) with a couple of other restrictions.  Berrian obviously helps this, but noone else the Bears lost does (Ayanbadejo, Gilmore, and Jimmy Kennedy.)  Coming in are Booker and Lloyd, who have low salaries and playing time is a wildcard.  That still leaves us with a big loss vs. potentially no big gains and an overall net loss of players, which would result in a decent pick.  

One thing I don't quite know is if re-signing players during the free agency period (Briggs) affects this.  If it does that evens things out.  And of course free agency isn't over yet so the net loss vs. gain could change, and that seems to be a pretty big factor.    

Anyways, sort of boring and technical article but pretty interesting as it covers a little known topic.  

http://sportsnewssouthwest.com/nfl/projecting-the-2008-nfl-compensatory-picks.html