Game Probabilities - Week 16

Weekly game probabilities are available now at the nytimes.com Fifth Down. This week I also look at just how big a blowout Monday night's Giants-Redskins game was using the WP model.

Troy Polamalu and 'WPA Plus/Minus'

Troy Polamalu is one of my favorite players in the league. As a Ravens fan whose heart despises everything that is black and gold, I'm compelled to say that he is truly spectacular. (The picture to the left is his interception return for a touchdown that saved the AFC Championship game for Pittsburgh last year.) He's also a classy and selfless player who never showboats, a breath of fresh air in today's NFL. Unfortunately for Steelers fans, his injury this season has revealed just how great a player he is.

Polamalu has played in five games this season and has missed nine. Using the Win Probability (WP) model, we can calculate the Win Probability Added for any play (WPA). We can also sum WPA for any team, squad, or player to estimate the context-dependent contribution of that player to his team's chances of winning.

WPA for defensive players is particularly problematic. If a running back evades all ten other defenders but is tracked down 60 yards later at the 5-yard line by the eleventh, it's the tackler that will show up in the play-by-play and be charged with the loss in WP. That doesn't make sense.

But Polamalu's 2009 season provides us with a special opportunity. We can measure the WPA of the entire Steelers defense when Polamalu is playing and compare it to the WPA of the Steelers defense when he's not.

Team Playoff Probabilities - Week 16

Courtesy of NFL-Forecast.com, here are the latest playoff forecasts.

The Ravens have further strengthened their position in the AFC, while the battle in the NFC continues to be a battle between the Giants and Cowboys. The Cowboys currently have the upper hand, but the Packers' loss last week has made them vulnerable. The Ravens' weekend was miraculous. They won, while the Jaguars, Jets, Dolphins and Broncos all lost. Except for the Steelers, who still only have a small chance of making the playoffs, every single other competitor for the AFC wildcard lost ground. The Ravens went from the 'outside looking in' to the #5 seed.

Team Efficiency Rankings - Week 16

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.

Desperation Graphed

[Note: I can't remember if I already posted this or not. I did this back over the summer and saved it for the season. But I don't think I ever clicked 'publish.' ]

How desperate do NFL coaches have to be before they start going for it on 4th down?

Recently I've shown that, as a rule, teams should be going for it on 4th down far more often than they currently do. But what is 'currently do?' How far do coaches let themselves get backed up against the wall before they start actually doing what's best for their chances of winning?

Games of the Week

Tonight's game notwithstanding, the game of the week was the Oakland upset over Denver (6.2 EI). The runner up was the Green Bay-Pittsburgh barnburner (5.8 EI), which was also the comeback of the week (33 CBF).

Unlike last week, there was a good number of competitive games, including:
CLV 41 KC 34
CIN 24 SD 27
IND 35 JAX 31
MIN 7 CAR 26 (which despite the score was very close until the 4th qtr).

Explanations for Excitement Index (EI) and Comeback Factor (CBF) can be found here.

Was the Steelers' Onside Kick Smart?

Up by 2 points with 3:58 left against the Packers, Steelers head coach Mike Tomlin called for an onside kick. Was this a good decision?

When onside kicks are expected, they are successful only about 20% of the time. But unexpected onside kicks are successful a surprising 60% of the time. I think we can say this particular kick was certainly unexpected. And surprise onside kicks can be the most beneficial when a team is ahead late in the game. Possession is critical.

Roundup 12/19

If you're snowed in like me this Saturday afternoon, you've got plenty of time on your hands. Early season college basketball doesn't really grab my attention. Neither does the apparently sponsor-less "New Mexico Bowl." (Actually, I often root for Fresno State due to being stationed nearby at Naval Air Station Lemoore, CA for many years.) Here are some links to help pass the snowy Saturday.

Chase Stuart from PFR looks at Steven Jackson's huge year for the struggling Rams. That's very unusual for a RB to have such a big year on a losing team. In a contribution to the Fifth Down Blog, Chase looks at the five least likely playoff teams in history based on their early season struggles.