NYT: Game Probabilities - Week 7

Weekly game probabilities are available now at the nytimes.com Fifth Down. This week I also look at how the Chargers can be so dominant statistically yet only have two wins to show for it. It's something more in depth than my usual lead-ins for the game probabilities.

Here's an excerpt along with a graph I did not include in the original post:

"Successful plays are not enough. Consecutive successes are required to win.

...Two equal teams could each have 12 first downs in a game. One team could have three drives of four consecutive first downs, each leading to a touchdown, and the rest of its drives could be three-and-outs. The other team could have 12 drives consisting of one first down followed by a punt. Both teams could have equal yards, first downs and efficiency stats, and yet one team could win, 21-0. It’s easy to imagine a game in which one team has many more first downs and yards, but still loses. Could something like this bunching effect be cursing the Chargers?

SR Rankings - Opponent Adjusted

Here is an alternative set of rankings based on Success Rate. (You can learn more about SR at this post, and up-to-date advanced team stats, including SR, are always available here.) Beginning this week, each team's SR is adjusted for opponent strength.

The table below also lists each team's opponent SR, except when playing the team of interest itself, for offense, defense, and in total. I realize this may be a little confusing, so I shaded the columns. The shaded columns represent the team's own adjusted SR, while the white columns represent the team's opponent SR. Each team's total adjusted SR is in the far right column.

Each column is sortable. You can sort by division to see how each team shakes out within its own neighborhood. Note that the three top teams come from the NFC East, and that's not good news for my loyal Washington Post readers.

Washington Post: Where is the Redskins Defensive Line?

Today I've got another post up at the Washington Post's Redskins Insider site. This time I look at how the Redskins defensive line is holding the team back.

• There were many ups and downs in Sunday night's game against the Colts, but one sequence of two early plays completely changed the complexion of the game.
• The Redskins have been lucky with turnovers so far, but you can't count on that luck to continue.
• LaRon Landry is leading the league in tackles, but that's one record a safety does not want.
• Linebackers London Fletcher and Rocky McIntosh are picking up the slack for the DL.
• One key in the Redskins' upcoming game against Chicago will be getting to Jay Cutler. His sack rate is jaw dropping.

Efficiency Rankings - Week 7

Recently, I've received a handful of inquiries about how these rankings work. With teams like the 2-4 Chargers and 1-5 Cowboys at the top of the rankings, that's understandable. I thought it might be helpful to explain some things in plain language.

These are not 'power ratings' or my personal estimations of team strength. They're not necessarily the teams I think will make the playoffs. They are simply rankings in order of team efficiency.

I found that efficiency, more than anything else, correlates with, and is predictive of, winning. So the model focuses on net passing and running efficiency on both sides of the ball. It also considers turnover rates, such as interception per attempt and fumble per play. Penalty yards per snap is also included. All of these factors are weighted according to how well they mathematically correlate with team wins.

What makes this model unique is that it distinguishes between factors that are explanatory (telling us why teams won past games) and factors that are truly predictive (telling us why teams will win future games). For example, turnovers and turnover differential account for a very large part of why teams won previous games. But turnovers are extremely random from week to week, and teams are not consistent from one part of the season to the next. They're obviously not entirely random. (Peyton Manning will never have a 4% interception rate--3% is league average), but a very large part of the variance in interception rate can be accounted for by randomness. In other words, Eli Manning might have a 3.9% interception rate so far this year, but it's far more likely that his future games will be much closer to the league average of 3% than they will be to his current 3.9%. So factors like interception rate, which are relatively random, get heavily discounted in this model, especially early in the season.

Punt of the Year

The impact of every play is amplified in overtime, even punts. During the Patriots OT struggle with the Ravens last Sunday, punter Zoltan Mesko may have made the punt of the year. Facing a 4th and 6 from their own 16, Mekso was called in try to bail out the Patriots.

Typically, punts from that region of the field net about 39 yards, putting the Ravens at their own 45, and it looked like the Ravens were going to win the field position battle. From there, it only takes one or two first downs to move into striking distance for a game winning FG attempt. When Mesko trotted onto the field, the Patriots' win probability (WP) was 0.33.

Mesko’s punt went for 65 yards, aided by wind and by poor fielding by the Ravens returner. When the ball came to rest on the Baltimore 19 yard line, the Patriots had gained the upper hand with a 0.54 WP. The punt was worth +0.21 Win Probability Added (WPA), an impact extremely rare for a punt that neither results in a long return nor a fumble.

Tackles By Position

In researching my weekly post at the Post, I took a look at team tackles by position. In the off-season, I created a nifty stat called Tackle Factor (TF--available at the individual stats pages) that attempts to make sense of tackle statistics. Conventional tackle stats can be very misleading. Porous defenses allow more plays than stout defenses, creating additional tackle opportunities for below-average defenders. Additionally, some positions should be expected to have more tackles than others.

I wanted to see how the Redskins' defensive lines were performing. I figured that the larger the share of a team's tackles that a line accounts for, the better it's probably playing. I created the list below, which shows the percentage of tackles by each position group for each team.

Obviously, there is going to be some expected differences between defenses that are primarily 3-4 schemes and primarily 4-3 schemes. This is due to the relative number of defenders at each position and each position's role in the respective schemes. Additionally, the numbers can be skewed by late-game strategies of either running out the clock or desperation passing. Still, we might learn something by looking at where the tackles are being made.

The Weekly League: Notes and Ideas for Week Six

This week's edition of The Weekly League features:

1. Some notes on the peculiar joy derived from the current iteration of the San Diego Chargers, a team whose generic win probability (GWP) surpasses considerably its actual win-loss record.
2. An examination -- via some white-hot tables -- of the NFL's luckiest and unluckiest teams (as measured by GWP versus current, actualy win-loss records) through Week Five.

and

3. A table that proposes to offer something called "EPA Standings" -- itself an idea of minimal importance -- followed by even less important comments.

Let The Weekly League into your life, America!

As usual, a glossary of all unfamiliar terms can be found here.

Idle Thoughts on the Chargers
As our fearless leader Brian Burke noted recently in these electonic pages -- and as reader James noted even more enthusiastically in the comment section -- the San Diego Chargers are frigging awesome right now. The team currently sports a GWP of 0.81 -- this, despite an underwhelming strength of schedule (as suggested by the team's 0.42 opponent GWP). They feature one of the league's better defenses and the best offense.

Roundup 10/16/10

NFL Forecast has fresh playoff probabilities.

Peter King smartly uses efficiency stats (and not total yards or points--awesome!) to diagnose the Saints' troubles this year.

What are the odds?

I recently read this over at Cold Hard Football Facts: "Running is part of football. Always has been, and always will be. The problem from an analysis standpoint is that no one has come up with a way to demonstrate how running helps teams win. But that’s a shortcoming of NFL analysts, not a shortcoming of the running game." Hopefully, now there is one fewer shortcoming.

Platooning QBs? One year when I was at Navy we did that. We had one QB who was a passer who played between the 20s, and one guy who was the runner to played near the goal lines. I think we went 1-10 that year, with the only win against Army.

Last week was a bad one for #1 pick QBs.

Don't sleep on the Titans this season.

Over at the Community site, Chris Alan gives updates his analysis on surviving in a suicide league. Have your own research or analysis you'd like to share? Send it in to Advanced NFL Stats Community.