Early on in the 2010 season I was highly critical of Kansas City Chie..."/>

Early on in the 2010 season I was highly critical of Kansas City Chie..."/>

Dissecting Matt Cassel (and his completion percentage) With Pro Football Focus


Early on in the 2010 season I was highly critical of Kansas City Chiefs QB Matt Cassel. Cassel had a slow start to his 2010 season and I was becoming concerned that the talent around him was no longer holding him back, but instead was passing him by. My concern was that by midseason, Matt Cassel would be holding the Chiefs back.

Fortunately for the Chiefs, I was wrong. Cassel’s play improved greatly throughout the course of the season. He seemed to become more accurate with his throws, while at the same time developing a pretty good pocket awareness. He greatly limited his mistakes, hardly ever throwing an interception. He showed up when his number got called in the redzone and threw a career high 27 touchdown passes.

Early in the 2010 season, I was greatly concerned with Cassel’s poor completion percentage.  Cassel had a couple of miserable games early. In Week 1 he completed only 45.5% of his passes and turned in another poor performance against the Indianapolis Colts with a 55.2% showing. In fact, Cassel failed to turn in a completion percentage above 59.3% in the first four games of the season. This was when my criticism of the QB was at it’s highest.

Then Cassel turned in two strong efforts in a row vs. the Texans (69%) and the Jaguars (72.2%). He backslid in two straight overtime games against the Raiders and the lowly Bills (though to be fair, his drive at the end of overtime against Buffalo was inspiring) before rattling off three straight games where he completed over 60% of his passes.

It seemed Cassel was slowly starting to come around. He was up and down for the rest of the season but fantastic games against the Seahawks and Titans, as well as an incredibly gutsy performance against the St. Louis Rams following an emergency appendectomy, had the city of Kansas City starting to believe in Matt Cassel.

The season ended on sour note, both for the Chiefs and Cassel. The QB followed his best game of the season vs. the Titans (24 for 34, 314 yards, 3 TDs, 0 TDs, 70.6 completion percentage) with his two worst games of the season. In the season finale against the Raiders and the playoff game against the Ravens, Cassel went a combined 20 of 51 for 185 yards, 0 TDs and 5 INTs.

In all fairness, Cassel is still a developing QB, the Chiefs are still a developing team and the Raiders and the Ravens had two very tough defenses. The Chiefs still had some very apparent weakness, particularly at WR. They also had three key players, Thomas Jones, Brian Waters and Casey Weigmann, showing their age down the stretch. The 2010 Chiefs were young and not very deep and while I’m not making excused for Cassel’s deficiencies, one can’t deny that he made vast improvements from 2009 to 2010. Teams don’t go from 4 wins to 10 wins with a bum QB no matter how easy their schedule is and no matter how many other solid players they have. If you don’t believe me, just ask Jamarcus Russel and the Raiders and Derrick Anderson and the Cardinals.

Now that we have all of that out of the way, I want to talk a little bit about a new stat introduced by our very good friends at Pro Football Focus. If you’ve been reading AA long enough, you know that PFF is our most trusted resource for accurate interpretations of individual and team performances that go beyond your typical NFL box score.

PFF recently released an interesting article regarding QB’s and completion percentage. Being a big proponent of QB’s completing at least 60% of their passes, I read the article with great interest. What PFF is getting at in the article is that not all completions are a QB’s fault. There are all kinds of things that get marked down in the box score as an incompletion that don’t have anything to do with the talent of the QB. Things like WR drops, spikes to stop the clock, throwing the ball away when no receivers are open, certain batted and deflected passes and poor offensive line play are just a few of the outside factors that can hurt a QB’s completion percentage. In fact, according to PFF, 16-25% of all incompletions in the NFL are not the QB’s fault.

Here is a bit more on the subject from PFF:

"The chief evidence against this is the dropped pass. Of the 6762 incomplete passes that occurred in the 2010 regular season, we attributed 15% (1041) to drops by receivers. On traditional stat sheets, the quarterback is credited with an attempt and an incompletion and, in turn, his completion percentage takes a hit. Receivers, historically, haven’t had a mark against them despite fully owning the mistake. Only recently has the mainstream begun to focus on drops.Tom Brady, Shaun Hill, Colt McCoy and the Manning brothers all had 20% or more of their passes fall incomplete as a result of their receivers dropping the ball. This clearly shouldn’t be held against them and greatly hurts their completion percentage."

And a bit more:

"Quality of the players around the quarterback, pass routes, game situations and quality of the defense are among the factors that affect the difficulty of a throw. Another aspect, one that we can quantify, is the distance a pass is thrown. As you would guess, the further a pass is travels in the air, the less likely it is to be completed. In 2010, passes thrown behind the line of scrimmage were completed 87.2% of the time. Passes between 0 and 10 yards were completed 72.3% of the time, between 10 and 20 yards the number dropped to 55.8%, and passes beyond 20 yards were completed just 33.8% of the time."

This all makes so much sense but it would take entirely too much time for the official box score to contain statistics as accurate as a site like PFF. Thus, the folks over there are working on a system in which they can get a more accurate completion percentage for NFL QB’s.

Here is their breakdown of their methods:

"Below, we have a short table highlighting a new PFF stat called “Accuracy Percentage.” It takes the basic completion percentage idea and adjusts for the problems we’ve just discussed. All the passes a quarterback delivered on target (caught or not) are divided by the passes he truly attempted. It doesn’t yet account for the difficulty of the pass, but it’s a step in the right direction. It’s derived:(completions + drops) / (attempts – spikes – throw aways)Most notable in this Top 10 from 2010, are the jumps that Shaun Hill and Colt McCoy make when when their dropped passes, throw aways and spikes are accounted for. (Matt Schaub and David Garrard are who they bumped from the top group.) Also note that the two Dallas QBs experience a lesser change in this new look as they combined to have only 27 of their 531 passes adjusted."

How did Matt Cassel do with the adjusted stats? The original PFF article doesn’t tell us. They only list the top 10 QB’s. The top spot is held by Drew Brees and he is followed by Tom Brady, Tony Romo, Aaron Rodgers and Shaun Hill of the Lions. Click here to see the full top 10.

Not being satisfied with discovering this new data, I reached out to some of my friends at PFF and they hooked me up a spreadsheet of the full rankings.

Matt Cassel came in at…drum roll please…


Cassel finished 25th among QB’s who threw a qualifying number of passes. Not sure what number PFF used here but it was likely around 200 passes.* Cassel came in 25th out of 37 qualifying QB’s. He was just behind Sam Bradford and just ahead of Brett Favre.

*Clarification from Nathan of PFF. The QB’s on the list played at least 25% of their team’s offensive snaps.

Now remember, Cassel finished the season with an official completion percentage of 58.22. His adjusted completion percentage was 68.41%. Among these same QB’s, Cassel finished 30th in official completion percentage. While he was still only 25th after PFF made their adjustments, Cassel still saw his percentage go up by over 10%. That means, in PFF’s opinion, 10% of Cassel’s incompletions were not his fault.*

*I got another clarification on this from Nathan of PFF. Here is what he had to say:

"You said “That means, in PFF?s opinion, 10% of Cassel?s incompletions were not his fault.” . That is a slight mis-use of the statistic. You did 68%-58% to get the 10% difference. In order to find the % we thought wasn’t Cassel’s fault, you need to take that 10% and divide it by (100%-58%) to get 24.38%.I think probably the easiest way to explain why is an example. Let’s say a quarterback had an accuracy rating of 100%, which means that all of the incomplete passes were ether drops, spikes or throw aways. This would mean that all of the quarterbacks incompletions are not the quarterbacks fault. However if you took 100 minus their completion percentage, you would get some number that isn’t 100%."

It is important to keep in mind that while this may be more accurate than your standard completion percentage numbers, it doesn’t necessarily mean that Cassel is the 25th best QB in the NFL. As PFF mentioned in the article, they do not account for the difficulty level of the pass yet. That would probably explain why Browns QB Colt McCoy saw such a big jump. The Browns are a perfect storm because they were having McCoy run a West Coast style system that relies on a lot of short, quick passes. These passes are generally easier to complete. Unfortunately for McCoy, the Browns are very shallow on WR talent so his completion percentage took a big hit, despite the fact that more of his passes were of the shorter variety. This leads me to believe that the method of evaluation PFF is using here is pretty good, if not miles better than your standard box score completion percentage.

As Cassel continues to grow and as the Chiefs continue to add pieces around him, this will be a very interesting stat to look at again next year. I would be even more interested to see if PFF can figure out a way to weigh these stats by the difficulty level of the passes to even the playing field a bit. It is certainly an interesting exercise.

If any of you guys out there love analyzing stats, I highly recommend you consider purchasing a subscription to PFF’s premium stats. They have tons of awesome free content if you don’t want to pay but if you want to go a little bit deeper or you are thinking of starting your own football blog, it is a fantastic resource.

What do you think Addicts? I am anxious to hear your thoughts on this new evaluation system…as is likely evident by the 1600+ words I just wrote about it.