The Art Of The Interception: Good Hands And Randomness

So I wanted to take a further look at the topic I stumbled into last weekend: individual defenders' ability to pick off a pass.

I am using this idea to build into my 2012 team profiles, but let's spend a few minutes looking at individual players. Below are players who 1) ranked in the nation's Top 50 in Passes Defended last year and 2) are returning in 2012. I simply took a look at the number of passes they defended per game in 2011 and projected how many interceptions they should have had if they had pulled in 21.9% of their passes defended. This comes with some obvious disclaimers:

1. Not everybody has the same set of hands. Some defensive backs have great hands, while others are defensive backs (and not receivers) because their hands leave something to be desired.
   
   
2. If we were to use this as "projections" for 2012 -- as in, how many passes might they intercept next year? -- we would have to assume that they will see the same number of passes in 2012. That might be a faulty assumption because, quite simply, you develop a reputation after a while. Players on this list got quite a few opportunities to prove what they could do. Next year, someone like Merrill Noel, E.J. Gaines or David Amerson (i.e. a player who came out of nowhere in 2011) might not get as many opportunities to break passes up, simply because opposing quarterbacks might be choosing to look toward the other side of the field. That is one of the limitations of using individual Passes Defended data -- a lot of the country's best defensive backs didn't make this list because quarterbacks did not try to throw at them very much (because they're among the country's best defensive backs). Still, consider this a thought exercise as much as anything. It suggests that players like David Amerson and Bacarri Rambo may have been a bit lucky in both the opportunities they received and the balls they actually pulled in. Meanwhile, players like Merrill Noel, Josh Robinson, Najja Johnson or Marc Anthony either have awful hands or might pull in a couple more picks next year (if given the chance).

When I looked at the list of last year's top pass defenders, my thought was that, for most of them, their percentage of interceptions would regress back toward the mean of around 22%. Now I'm going to investigate that assumption.

After the jump is a look at 89 players who, between 2007-11, ended up on the Top 100 Passes Defended list in back-to-back seasons. I listed them in order of their %INT (the percentage of their passes defended that were interceptions) in their second of the two seasons. While they defended a similar number of overall passes from one year to another, what can we learn about the number they intercepted?

As you'll see, there is but a small correlation (about 10 percent) between a player's percentage of interceptions in one year with their percentage in the next. Someone like Kent State's Brian Lainhart, who picked off 55 percent of his passes defended in 2008, then picked off 64 percent in 2009, may have had really good hands. Meanwhile, someone like Alabama's Kareem Jackson (nine percent in 2008, seven percent in 2009) may have had a decent set of stone hands. But players like Vanderbilt's Myron Lewis (8 percent in 2007, 46 percent in 2008) or Nebraska's Prince Amukamara (31 percent in 2009, zero percent in 2010) illustrated that there really is quite a bit of randomness involved.

To further illustrated this point, let's look at some averages. Here are the 89 players below, grouped in order of their second-year %INT.

• Top 9 -- 52.2% INT in second season, 40.4% INT the previous year
• Next 10: 41.3% INT in second season, 25.3% INT the previous year
• Next 10: 32.7% INT in second season, 39.6% INT the previous year
• Next 10: 27.3% INT in second season, 28.7% INT the previous year
• Next 10: 23.2% INT in second season, 17.9% INT the previous year
• Next 10: 18.8% INT in second season, 26.8% INT the previous year
• Next 10: 14.1% INT in second season, 28.1% INT the previous year
• Next 10: 9.7% INT in second season, 18.7% INT the previous year
• Next 10: 4.7% INT in second season, 23.7% INT the previous year

At the very top, we might see evidence of certain players having really good hands/instincts. But outside of the very top names, last year's %INT has, basically, no bearing whatsoever on next year's %INT.

This is good news for players like Merrill Noel of Wake Forest or E.J. Gaines of Missouri, who combined to pick off five passes and break up 35 (combined %INT: 12.5%). It is also probably bad news for N.C. State's David Amerson, whose 72.2% INT rate was easily the highest of the past five years; even if he does have great hands, he probably won't have a %INT higher than about 40% or 45% this fall.

Bottom line: there is most certainly skill in defending a pass. It means you have great anticipation skills and agility, and each are quite obviously key components to playing well as a college defensive back. But the art of picking off a pass, as opposed to simply breaking it up, is a bit of a mystery and cannot be counted on from one season to another.