College Football Likelihood of Scoring a Touchdown

Just a quick post here as I start digging into the excellent college football play-by-play database available at cfbstats.com.

The database has touchdowns coded as either 1 or 0, so each play either is a touchdown, or isn’t.  That made it extremely easy for me to produce the graph below, which shows the likelihood of scoring a touchdown depending on whether a play is a pass or run.  Pass plays are represented by the blue line, while run plays are represented by the red line.  There’s an interesting bump in the red line at the 25 yard line that I’ll probably try to dig into.  The PBP database includes about 400,000 observations of both run plays and pass plays, so I suspect the bump is real.  It could be the case that run plays from the 25 have the defense just a little more stretched out than a run play from say the 18 yard line, and therefore the odds of scoring a touchdown from the 25 are slightly greater.  Anyway, it’s something interesting to look at further.

Run Plays = Red Line

Pass Plays = Blue Line

Rplot11

Further to the Interaction Between Quarterbacks and Receivers

One of the challenges with any kind of a quantitative system in football is that the interactions between players are extremely difficult to get a handle on.  In the simplest terms, when Matthew Stafford throws the ball to Calvin Johnson, how much credit should Stafford get for the play and how much credit should Johnson get?  That’s as easy as it gets.  Now what do you do when Stafford throws to Tony Sheffler who is open because the defense is primarily concerned with stopping Calvin Johnson?  Who gets the credit for the play then?

According to Advanced NFL Stats, the greatest season that Randy Moss has had since their numbers began was in 2000 when he added 0.16 Win Probability Added/game.  During that same season ANS credits Duante Culpepper with 0.28 WPA/game.  But I consider it more likely that Randy Moss had a larger effect on Culpepper’s value, than Culpepper did on Moss’.  Culpepper hasn’t done anything without Moss, whereas Moss allowed all of Culpepper, Randall Cunningham, and Tom Brady to have career years throwing to him.  So what are we to think then of the fact that Culpepper’s WPA exceeds Moss’ when Moss is probably having all sorts of impacts on the game which can’t be measured.  This isn’t an argument against advanced stats or even against Brian Burke’s WPA formula.  It’s just a continuation of my argument that there is more to a passing game than a franchise QB.

Consider that for the 2006 season, ANS credits Tom Brady with .11 WPA/game.  In 2007, his WPA jumps to .38 WPA/game.  Consider also that for the 2008 season, ANS credits Matt Cassel with .18 WPA/game and then that number dives to –0.15 WPA/game when Cassel leaves the Patriots for the Chiefs.  So the effect of adding and removing Randy Moss/Wes Welker was +0.27 in WPA/game for Tom Brady when he gained those WRs and it was –0.33 for Cassel when he lost those WRs!  Also worth pointing out is that Matt Cassel with Moss/Welker was worth more in terms of WPA than Tom Brady before he had them.

Probably an important point here is that I’m not arguing against the value of Tom Brady.  This is a two way street.  Consider the following graph which shows my fantasy scoring efficiency measure for Andre Johnson.  You can see exactly when Matt Schaub got to Houston.

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But the relationship goes the other way too.  Here is Matt Ryan’s fantasy scoring efficiency graph.  You can clearly see when Julio Jones got to Atlanta.

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To go back to the Patriots and what happened when they added Randy Moss and Wes Welker, consider that according to Advanced NFL Stats, this would be the ordering of the passing games in terms of WPA during the 2006-2008 time period.

  1. Brady/Moss/Welker
  2. Cassel/Moss/Welker
  3. Brady/Reche Caldwell/Jabar Gaffney

Obviously the optimal situation is a franchise QB with two wide receivers who can get open at will.  But dumpster-fire-QB with two wide receivers who can get open at will ends up beating the franchise QB with two scrub WRs.

A Half-hearted Defense of Brandon Weeden (Along With a Moneyball Strategy)

Going back to the 2005 draft, the Browns have used the following draft picks to select quarterbacks:

2012, 1st Round – Brandon Weeden

2010, 3rd Round – Colt McCoy

2007, 1st Round – Brady Quinn

2005, 3rd Round – Charlie Frye

The Browns’ record at selecting QBs isn’t very good and depending on how Brandon Weeden’s career shakes out, they have a real chance of going oh-fer on that series of QB picks. 

But the Browns’ attempts to fix their QB position haven’t been limited to the draft.  In 2010, the Browns also signed Jake Delhomme as a free agent, gave him a signing bonus of $6 million and paid him a year’s salary, after which time they released him to avoid paying an additional $5 million.  The Browns also traded a late round draft pick in 2010 in order to acquire Seneca Wallace from Seattle.

Depending on how much you read into Cleveland’s courtship of Chip Kelly and the likely implications that a Kelly hire would have had for the Browns, you could get the sense that they might be willing to throw Brandon Weeden on the scrap pile and start over again.  I think that would have been a mistake (ditching Weeden would have been the mistake, not hiring Chip Kelly as that would have been fantastic I’m sure).

If I had to guess, I would say that Brandon Weeden has the potential to be a decent but not great quarterback for a few years.  This is based on a few things.  First, I think he can make all of the needed NFL throws, which is something.  He’s not going to hamstring an offense because he can’t throw to the deep part of the field.  However, on the flip side, Weeden probably had about as much talent around him this year as Andrew Luck did, and Andrew Luck wildly outperformed him.  So my position is basically that Weeden could be a serviceable QB if given time to adjust to the NFL and also his ceiling probably isn’t anywhere near Luck’s ceiling.  But I also don’t think Weeden’s age matters at this point.  It might have mattered before the draft last spring, when the Browns should have been doing some math on the expected value of a QB of Weeden’s age, but it doesn’t matter now.  The Browns already burned the pick to get Weeden, so the only cost going forward is his salary.

I think there is some room for optimism related to Weeden because he wasn’t 100% bad this year.  He was maybe only 80% bad.  When Weeden was throwing to Josh Gordon, the QB averaged 8.2 Adjusted Yards per Attempt.  That’s very good.  Matthew Stafford averaged 8.97 AYA when throwing to Calvin Johnson.  So we know that if Weeden is throwing to the right receiver, he’s not awful, and that’s true even if the receiver was a rookie who didn’t play in any college games last year.

Now let me move on to a related point.  Since the 2000 draft, NFL teams have taken 36 QBs in the first round, while they have taken just 52 wide receivers.  That strikes me as being too low for wide receivers.  If we added up team snap counts, would receiver snap counts be greater than QB snap counts by 2X?  2.5X?  I’m sure PFF has this info, but let’s just assume 2.5X for now as a team will start 2 outside receivers and then they’ll have a mix of 3 and 4 wide receiver sets as well.  So if receivers were drafted at the same rate as QBs and proportionate to snap counts, closer to 90 WRs would have been taken in the first round since 2000.

This strikes me as being a case where teams aren’t correctly gauging supply and demand.  Even though the elements of a passing game are highly interrelated, they tend to view their quarterbacks in isolation and then go looking for them in the draft even though all of the other teams are going through the same haystack hoping to find the same needle.  I think that given the price bubble that essentially exists in the draft related to QBs, teams should try to fix their passing games in a way that is more contrarian in nature.  Instead of going back to the draft repeatedly to try to find that QB, use the pick on a WR instead and try to make the game easier on your QB.  To put it another way, would Weeden have been as bad if every receiver he was throwing to could produce at the level of Josh Gordon?

Let’s return to the Browns’ picking of QBs in the draft.  Consider that when Cleveland picked Brady Quinn in 2007, the next player off the board was Dwayne Bowe.  When the Browns took Colt McCoy in 2010, the next receiver off the board was Eric Decker.  You can actually even go further back and see that when the Browns took Charlie Frye in the 3rd round in 2005, the next WR off the board was Chris Henry, who had a short but promising career before he died.  Cleveland was burning through picks taking QBs, and while that is a very important position, they were probably leaving better players on the board when they did it.

This strategy might not even be limited to the draft.  You could also do the same thing in free agency.  Consider that Alex Smith will be a popular name that will come up as teams try to put a band-aid on their QB position.  Alex Smith has about a $9 million cap hit this year, so that might be a good gauge as to his cost.  Let’s say that instead of using money to sign Alex Smith, who is a band-aid at best, you used it to sign Mike Wallace.  It’s reasonable to assume that Mike Wallace could be had for about the cost of Alex Smith because Vincent Jackson was probably a similar (or better) quality free agent WR and he is on an $11 million/year contract with no guaranteed money.  So what would happen if the Browns tried to fix their QB situation by adding Mike Wallace instead of a QB? 

Look at these two passing units and tell me which one you would prefer:

  Scenario 1 Scenario 2
QB Brandon Weeden Alex Smith
WR Mike Wallace Travis Benjamin
WR Josh Gordon Josh Gordon
WR Greg Little Greg Little

 

I would personally be a lot more optimistic about the scenario involving Brandon Weeden and Mike Wallace.  Scenario 1 seems like a huge improvement for the Browns, while Scenario 2 seems like maybe a mild improvement.  Looking at the same issue from another angle, if you were a defensive coordinator, which unit would you rather go up against?  This strategy just focuses on the idea that you can get a lot of wide receiver for the price of a mediocre (at best) quarterback.  That’s true in the draft, and it’s probably true in free agency as well.

I think there are two potential objections to my strategy which essentially focuses on the relative supply/demand opportunities that exist in the QB and WR markets.  Those objections are as follows: The Arizona Cardinals, The Kansas City Chiefs.

Both the Cardinals and the Chiefs did the equivalent of trying to pile up at WR when they took Michael Floyd and Jonathan Baldwin in the draft.  But the problem with those draft picks is that in each case, the teams took guys who hadn’t really dominated at the college level and we know that receivers who don’t dominate their college games have longer odds to be good pro receivers.  Models that project college wide receivers to the pros tend to place emphasis on touchdowns, of which Michael Floyd had just 9 in his senior year at Notre Dame, and Jon Baldwin had just 5 in his last year at Pitt.  We can look at a team like the Packers in order to see how this strategy might be executed more effectively.  Greg Jennings and Jordy Nelson were 2nd round picks who both scored extremely well on algorithmic projection systems coming out of college.  Jennings had 14 touchdowns in his senior year at Western Michigan, while Nelson caught close to 50% of all of the yards that Josh Freeman threw in 2007 at KSU.  Nelson also scored 11 touchdowns that year.  Randall Cobb is another name that looks good if you add up his rushing and receiving touchdowns, as he scored 12 combined touchdowns in his last year at Kentucky.  Aaron Rodgers is probably an otherworldly QB, but the Packers also haven’t been sitting on their hands, making him do all of the work.  They’ve been ensuring that he has the weapons he needs in the passing game.

A formula that explains NFL passing success would be difficult to nail down because you have issues projecting the success of individual pieces and you have issues figuring out how the pieces will interact with each other.  For instance, Wes Welker is a very good receiver and Tom Brady is a very good QB.  But it’s probably also the case that they work better with each other than either of them would work with another similar quality player.  For this reason, you can’t really blame NFL teams that have a difficult time isolating their problems when they try to fix their QB position.  What I’m arguing though is that trying to fix your QB position is a proposition that includes high costs and low success rates, while the wide receiver market has more opportunities for value.

If you can fix your team by replacing your QB with a can’t miss prospect like Andrew Luck, then you should do it.  But Andrew Lucks don’t come along very often and this strategy is one that acknowledges that reality and looks for ways to improve a passing game through relative value opportunities.