This post probably has more to do with an interesting query result than suggesting an alternative strategy for coaches. I was taking a peek at the 2005 play-by-play data that is available on this site (thanks Brian!). I had just separated everything into drives and series. I was wondering what the most efficient pass/run mix was, historically. One of the funny looking query results that I turned up was the following matrix of down-and-distance and conversion percentages. This data is limited to the 2005 data and does not include first downs gained by penalty. Nor does it exclude garbage-time drives or time-pressure drives. It does include playoff games and goal-to-go series.
|Down||Distance||Pass Conv%||Run Conv%|
To me it is interesting to see that running is a better strategy on
3rd down for distances of 6 yards and less. One of the reasons that running is so effective is that it is apparently unexpected. The next table shows the same down-and-distance situations, and how many of each type of play occurred in the league.
|Down||Distance||Pass Plays||Run Plays|
On 3rd down and 3, 76% of teams pass instead of run. And thepercentage of passing on 3rd down with more yards than 3 needed for a first down only gets higher. So most defenses on 3rd and 3 or higher will be implementing a pass-oriented scheme and personnel package. And 3 out of 4 times (or even more often) they will be making the correct call. Given those circumstances a run play would be expected to be more successful. And apparently, it is. According to game theory, if coaches were calling the correct run/pass mix, the conversion percentages would be nearly identical. For 3rd and 6 or less, they aren't. So the obvious assumption is that more running plays should be called on 3rd and 6 than are currently being called in the NFL. Of course, this post would need to be backed up by data from more than one year to validate any assumptions made.