In a recent article I presented evidence that offenses should generally pass more often on first down. Accounting for both the potential gains and the potential risks of each type of play, passing tends to lead to a greater net point advantage than does running. The analysis was based on a concept known as Expected Points, which measures the average point advantage an offense can expect given a down-distance-field position situation.
Expected Points incorporates all the various factors such as turnovers, yardage gains, sacks, incompletions, first down conversions, scoring, and so on. But I thought it would be helpful to dig deeper to investigate how and why passing appears more advantageous. In this article, I'll present a series of graphs comparing running and passing on first down, each one looking at a different facet of the game.
(Much) More on 1st and 10 Run-Pass Balance
Sunday Night 4th Down
Down by 3 with a little more than 3 minutes left in the game, Ravens head coach John Harbaugh faced a decision with a 4th and 5 at his own 48. Harbaugh decided to go for the first down. Both Al Michaels and Chris Collinsworth agreed Baltimore had no choice but to punt. Was it a good call?
Punts from the 46 net an average of 34 yards, which would put the Steelers at their own 20. In that situation, teams win 83% of the time. A punt gives the Ravens a 0.17 win probability (WP).
Conversion attempts for 4th and 5 situations outside the red zone are successful 48% of the time. An unsuccessful attempt leaves the Steelers with a first down at the Ravens' 46. Teams win 87% of the time from there, leaving the Ravens with a 0.13 WP. A successful conversion would, at worst, give the Ravens a first down at the Steelers 49, worth a 0.37 WP. On net, the conversion attempt is worth:
Andy Reid: Hero
Reid was my goat of the year for 2008 for the season's single worst 4th down decision, but today he's my hero of the day (or at least for the 1st quarter of the 1 pm games). Reid started the game with an unexpected onside kick, which is an underused but very worthwhile tactic. This time it didn't work out, but the Eagles recovered nicely, and now lead 10 - 7.
The linchpin of the Eagles's 1st quarter TD drive was a successful 4th down conversion. With a 4th and 1 on the Redskins' 42, Reid went for it, made it, and went on to take the lead (for the moment).
Team Playoff Probabilities - Week 12
Courtesy of NFL-Forecast.com, here are the latest playoff forecasts. The tables below do not include results from the Thursday games.
It looks like the AFC teams remain relatively firm. As of now, the Colts, Bengals, Steelers, Patriots, Broncos, and Chargers are on the inside track. Baltimore, Jacksonville, and Houston are on the outside looking in.
Not much has changed for the NFC either. The top teams have a tight hold on playoff spots, but the wildcards are up for grabs. The Saints, Vikings, and Cardinals each have a good grip on their divisions if they keep playing well. The Cowboys are the class of the East at the moment, and have a good shot at a wildcard if they don't take the division. The other contenders include the Eagles, Giants, Packers, Falcons, and the 49ers.
Game Probabilities - Week 12
Weekly game probabilities are available now at the nytimes.com Fifth Down. This week I also discuss the major shortcoming of a purely quantitative approach to game predictions.
Happy Thanksgiving, everyone!
Team Efficiency Rankings - Week 12
The team rankings below are in terms of generic win probability. The GWP is the probability a team would beat the league average team at a neutral site. Each team's opponent's average GWP is also listed, which can be considered to-date strength of schedule, and all ratings include adjustments for opponent strength.
Offensive rank (ORANK) is offensive generic win probability, which is based on each team's offensive efficiency stats only. In other words, it's the team's GWP assuming it had a league-average defense. DRANK is is a team's generic win probability rank assuming it had a league-average offense.
GWP is based on a logistic regression model applied to current team stats. The model includes offensive and defensive passing and running efficiency, offensive turnover rates, defensive interception rates, and team penalty rates. If you're scratching your head wondering why a team is ranked where it is, just scroll down to the second table to see the stats of all 32 teams.
Offenses Run Too Often On 1st Down
NFL offenses generally run too often on 1st down. Accounting for the relative gains of each play type, and accounting for the risks of turnovers, offenses should pass more. There is currently an imbalance, where teams are too often running directly into defenses that are expecting runs.
Game theory tells us that when there are two strategy options, like run and pass, the expected payoffs for both options should be equal. You really don't need game theory to intuitively understand this. If one option yields a better payoff, then it should be chosen until the opponent responds with a strategy change of his own. Eventually, as the opponent responds, the payoffs for the two options equalize. The point at which the strategy mix equalizes payoffs is known as the minimax, or sometimes called the Nash equilibrium. The resulting strategy mix, or run-pass balance in this case, produces the best overall, long-run payoff.
When there are two strategy options and one of them yields a much higher payoff, it tells us two things. In this case, passing is more lucrative than running on 1st down, and this tells us: 1) offenses should be passing more often, and 2) for now, defenses should continue to be more biased toward stopping the run.
Last Thoughts on the 4th and 2
At the risk of being accused of milking this thing, here are some final few thoughts on the topic. I watched the Football Night in America segment and a few things struck me.
Let me say I have a lot of respect for Coach Dungy. I also think that convincing someone skeptical is difficult, and we shouldn't expect someone to immediately come around. In general though, coaches (and former players/analysts) benefit from a perception that football is some unknowable mystery, and that they are the only priests that can divine the true answers.
From Dungy's perspective, he's enjoyed long career by doing it the conventional way. But the reason his way worked was because everyone else played the same way. To change his mind now might mean admitting, "I did it wrong all these years." That's a tough hurdle to overcome.