2010 Weak Side Runs: Using Game Theory to Call Plays
Throughout my film study articles, I have chronicled the trends of the Cowboys in specific situations, attempting to isolate the cause of their success or failure. Some statistics are subjective, such as missed tackles, but I strive to obtain statistics that are objective as possible.
In this study, I will analyze the Cowboys’ weak side runs. Like prior pieces, there is some “gray area” here. What is a weak side run? Is the weak side always opposite the tight end?
For this analysis, I have designated the weak side of the formation as that which is opposite the tight end and has less than three skill position players. Thus, in “Twins Left,” the right side is the strong side. In “Twins Left, Weak Left” (below), however, the left side is strong.
If a formation has no tight end, the strong side is simply the side with the most skill position players. Also, a multitude of formations have no strong or weak side, such as “Ace” (below).
The findings I gathered are listed below. The Cowboys averaged 4.72 yards-per-carry on weak side runs, compared to just 3.67 yards-per-carry on strong side runs, and 4.23 yards-per-rush on runs from balanced formations.
Why did the Cowboys have more success running weak side than strong? One possibility is that it surprises the defense. Dallas ran weak side on just 22.8 percent of all run plays (up from 19.5 percent in 2009). Thus, with the defense generally anticipating a strong side run, the success rate of running weak side increases despite a lesser number of blockers.
The lack of blockers to the weak side can also be a good thing because defenses generally line up according to the formation. Less blockers, then, means less people to block, and less chance for mistake.
If this theory is correct, we might expect the Cowboys percentage of big plays to increase significantly when running weak side. This is exactly what we saw in 2010 (although not in my 2009 results). The Cowboys ran for a play of 10+ yards on 13.8 percent of all weak side run plays in 2010, compared to only 6.5 percent on all strong side runs.
Further, the yards-per-carry, big play percentage, and negative play rate of runs from balanced formations (such as “Ace”) all fall between the corresponding numbers for weak and strong side runs. This is evidence that weak side runs are generally superior to strong side runs because hybrid formations (balanced formations are a sort of “hybrid” of strong and weak ones) create hybrid results.
How should this information affect the Cowboys and Jason Garrett’s play-calling? Well, as I detailed in my 2009 Witten blocking study, the play-calling should shift until it reaches the “Nash Equilibrium.” Simply put, this is the point when the overall yards-per-rush will peak.
Note that Garrett cannot simply call all weak side runs because football is a game of opposing minds. A drastic increase in weak side runs would obviously be met by a large percentage of defensive weak side blitzes.
Instead, game theory suggests Garrett should slowly increase the number of weak side runs until the average yards-per-carry is maximized.
But how will we know when that number is reached? The answer would be simple if we assumed those people drawing up plays to try to stop the Cowboys offense–the opposing defensive coordinators–were perfectly rational. In that scenario, the defense would call an increasing number of weak side blitzes until they minimized the overall yards-per-carry. They would in effect create their own Nash equilibrium.
Of course, defensive coordinators do not always call plays in a rational manner. Their knowledge is not unlimited, and so sometimes they may call too many weak side blitzes or not enough. Perhaps sometimes the number of weak side blitzes they dial up has no correlation at all with the offenses’s weak side running rates or successes.
Garrett’s job, then, must be to take into account the thoughts and tendencies of defensive coordinators (perhaps easier said than done), and then adjust his play-calling accordingly. If Team X calls an inordinate amount of weak side blitzes, for example, then the Cowboys own Nash equilibrium will be shifted to include more strong side runs (and vice versa).
Thus, play-calling (or effective play-calling anyway) is not simply about knowing your own players. It is about successfully predicting the calls of defensive coordinators by knowing their tendencies. This may sound extremely difficult (and it is from the standpoint of one individual play), but aberrations tend to flatten out over the course of a game in such a way that, despite not knowing individual play calls, a team can assume a “regression to the mean” of sorts where a team’s overall tendencies will always eventually shine through.
For Garrett, this means being one step ahead of the game. Instead of simply knowing what you want to do, you have to know what your opponent thinks you are going to do, then adjust accordingly. When playing against a really stealthy coach, you may have to know what he thinks that you think that he thinks about what play you are going to call.
If you are an offensive coordinator and have called three straight weak side runs in a row, for example, your natural inclination may be to deviate from this tendency. You might do this in an effort to “mix it up.” But game theory suggests you should take into account the opposition’s thoughts before making a decision.
Perhaps you know that he is thinking that you are thinking that he will call a weak side blitz to combat your recent success. Knowing this, you would assume he may call a strong side blitz (or none at all), and you would be correct. Thus, despite three straight weak side runs, the best play call is yet another weak side run.
Being “unpredictable” isn’t about changing play calls just for the sake of changing the play, but about adjusting your tendencies according to your opposition’s tendencies to create an environment where potential success will be maximized.