My 2012 Oklahoma State preview is up, so now would be a good time to talk for a moment about luck. It clouded the "How good is Oklahoma State's defense?" debate all year (and all offseason), and it is easy to go too far in generalizing the "turnovers = turnaround" lessons Phil Steele has taught most readers at this point. First things first: yes, there was some luck involved in OSU forcing 44 turnovers last year, and, therefore, yes, there was some luck involved in the Cowboys' plus-21 turnover margin. But not all turnovers are created equal.

Forcing fumbles: not luck. At least, not for the most part. OSU forced 18 of them in 2011 (seventh-most in the country), and, unprompted, opponents laid another nine balls on the ground as well. OSU forced 15 in 2010 as well. Going after the ball is at least partially by design -- Iowa State has forced at least 14 fumbles in all three years under Paul Rhoads, for instance, while Michigan State hasn't forced more than 13 in the last four seasons -- and OSU tends to do it well. They also do it across the board: OSU defensive ends forced six fumbles, linebackers forced six, and defensive backs forced six.

Recovering fumbles: mostly luck. When your team recovers a high percentage of fumbles, you claim it is because of passion and tenacity, but both teams tend to have that. The art of falling on a pointy, oblong ball is, really, not an art at all. It is lucky. So the fact that OSU recovered 74 percent of its opponents fumbles in 2011, and 60 percent of all fumbles, was at least a little bit based in randomness.

Defending passes: not luck. As with stripping the ball, some teams are much more aggressive than others when the ball is in the air. Oklahoma State defended 87 passes in 2011 -- they intercepted 24, and they broke up another 63. In 2010, they defended 76 (19 picks, 57 PBUs); in 2009, they defended 86 (18 picks, 68 PBUs). This is another facet of your typical Bill Young defense, and OSU has more than enough speed in the secondary to go after the ball successfully in this regard. The 'Pokes have ranked in the nation's Top 10 for passes defended in each of the last four seasons, in fact, so this progression began before Young even came aboard.

Intercepting passes: mostly luck. Yes, some guys have good hands, while others are made of stone. That makes a difference. But for the team as a whole, your ratio of interceptions to passes broken up is quite random. On average, 21.9 percent of all passes defended are interceptions. Over time, a team can expect to either regress or progress toward that number.

In 2011, the 120 FBS teams intercepted 1,436 passes and "broke up" 5,131. That means that 21.9 percent of what we call "passes defended" were interceptions. Only, the spread from team to team was enormous. For N.C. State, 43.5 percent of their passes defended were INTs. For Akron, 6.7 percent. I looked at this data from year to year and found that, though it would appear based somewhat on skill (N.C. State had David Amerson and Akron didn't, after all), a team's year-to-year percentages have almost no correlation. Georgia's Bacarri Rambo was second in the country in interceptions (eight), but in his three years of participation, the Bulldogs' ratio of interceptions to overall passes defended has gone from 19.6% in 2009, to 35.6% in 2010, to 27.0% in 2011. Some years, you catch them. Others, you don't.

In 2011, Oklahoma State defended 16.1 percent of the 541 passes their opponents threw. If they had picked off 21.9 percent of those defended passes, that would have resulted in 19 interceptions. Instead, they intercepted 24 passes. That suggests that somewhere around five of those picks were potentially based in luck.

Let's summarize: Oklahoma State's defense was absolutely a bit lucky in 2011. They picked off about five more passes than they probably should have, and they recovered about four more fumbles than they probably should have. A swing of nine turnovers can obviously make an enormous difference over the course of the season. (They did, after all, benefit from about 3.4 turnover luck points per game.) That said, this defense wasn't based entirely on lucky bounces. Yes, OSU allowed a ton of yards. (They ranked 107th in yards per game allowed.) That's what happens when you a) face Arizona, Tulsa, Texas A&M, Missouri, Baylor, Kansas State, Texas Tech, Oklahoma and Stanford, and b) do so with your own offense running at a nuclear pace (and therefore face a ton of plays).

But the 'Pokes were among the best defenses in the country at preventing big plays; they mastered the art of the bend-don't-break defense, forming a cloud, swarming to the ball, forcing opponents to run an extra play to score, then eventually forcing a mistake. You would of course rather have a defense like Alabama's or LSU's, well-coached and packed with four- and five-star talent (and speed to burn). But Young and OSU have figured out how to field a fast, aggressive, disciplined defense without the luxury of 25 blue-chippers. That shouldn't change much in 2012, even if the turnover margin does at least a bit.