Joe Buscaglia of WGR 550 had an interesting blog post on Friday investigating the success rates of quarterbacks drafted in specific rounds since the 1990 NFL Draft.
Essentially, the idea was to determine if an NFL team could find a starting-caliber quarterback with the same odds of success after the first round of a given NFL Draft. Buscaglia's "litmus test" is a bit subjective, using Chad Pennington as a point of comparison, but he also polled a colleague to determine the final results of his experiment, which removes some of that subjectivity.
The results are very interesting, to say the least. 46 quarterbacks have been drafted in the first round since 1990, and of those, 21 (45.7%) qualified as "hit" picks according to Buscaglia's system. 20% of second-round quarterbacks qualified, and less than 13% of third- and fourth-round quarterbacks panned out. The stark contrast between the first round and subsequent rounds was a bit surprising - and it's also very obviously difficult to get a good quarterback no matter where you pick.