Are Teams Going For It More In 2009?

Is it me, or do I sense that teams are going for it more often on 4th down this year? And maybe I'm imagining things, but I also get the feeling that teams have been even more daring since the Belichick 4th down decision against the Colts.

The three graphs below tell the story. The top two graphs depict the proportion of 4th down decisions by field position. The first graph is for the 2000-2008 seasons, and the second is for the 2009 season. The third graph isolates just the proportion of conversion attempts by field position so we can better compare the previous seasons with the current season.

Game Probabilities - Week 15

Weekly game probabilities are available now at the nytimes.com Fifth Down.

Team Playoff Probabilities - Week 15

Courtesy of NFL-Forecast.com, here are the latest playoff forecasts. The tables below do not include results from this week's Thursday game.

The Ravens have strengthened their position in the AFC, while the battle in the NFC appears to be between the Giants and Cowboys.

Expected Point Values

Lately I've been using the concept of 'Expected Points' (EP) as a measure of success for football plays. It's been the foundation of much of my analysis of fourth down decisions, onside kicks, run-pass balance, and even touchbacks.

Every down-distance-field position combination has an average net point advantage. For example, when an offense has a first and goal at their opponent's 1-yard line, they can expect about a 6-point advantage over their opponent in the long run. A first and 10 at midfield is worth about 2 EP.

Expected Points on first downs are easy to compute because there are so darn many 1st and 10s compared to any other down and distance combination. Here is the EP chart for 1st and 10 (or goal) from my fourth down study earlier this season.

Team Efficiency Rankings - Week 15

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.

Games of the Week

Some weeks can have a lot of really exciting games. Week 14 wasn't one of them. This week's most exciting game was (technically) BUF 16 KC 10 (5.5 EI). True, this wasn't a shootout between two playoff contenders, but if you really cared about who won, this was exciting. Leads of 6 points often produce exciting games because a TD at any time can tip the balance.

The runner up actually had playoff implications.

The comeback of the week wasn't terribly thrilling either. NE had about a 1 in 6 chance of winning (a CBF of 6) late in the second quarter as CAR drove into scoring position with a 7-point lead. NE ultimately won, NE 20 CAR 10.

Run-Pass Imbalance by Year

I've been chronicling the imbalance in the payoffs of runs and passes on first down in several recent articles. One of the possible explanations for the imbalance is that coaches are too slow to adapt to the NFL rules that seem to become friendlier to the pass year after year. If so, maybe the adaptation to the new realities can be seen in a decrease in the payoff imbalance over recent years.

The graph below charts the difference in payoffs between passes and runs by year. As with my previous posts, data are limited to 'normal' football situations--when the score is close and when time is not yet a factor. As you can see, there may be a slight decreasing trend in the imbalance, suggesting coaches might be catching up.

Team Playoff Probabilities - Week 14

Courtesy of NFL-Forecast.com, here are the latest playoff forecasts. The tables below do not include results from the Thursday games.

The Jaguars and Broncos have strengthened their positions in the AFC, while the Giants, Eagles, and Packers have improved their chances in the NFC.